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  • N‐doped Carbon Nanotubes Encapsulating Ni/MoN Heterostructures Grown on Carbon Cloth for Overall Water Splitting
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-16
    Pan Wang; Ji Qi; Chuang Li; Xiao Chen; Tonghua Wang; Changhai Liang

    Herein, we reported a new strategy to grow N‐doped carbon nanotubes encapsulating Ni/MoN heterostructures on carbon cloth (Ni/MoN@NCNT/CC). The high intrinsic activity in the interface engineering of the Ni/MoN heterostructures, the high conductivity and protection of NCNT, and the three‐dimensional structure of the Ni/MoN@NCNT/CC contribute to its outstanding activity and stability for HER (overpotential of 207 mV at 10 mA cm ‐2 ) and OER (overpotential of 252 mV at 10 mA cm ‐2 ). Particularly, for HER, it can maintain a consistent potential at 100 mA cm ‐2 for 100 h. Besides, for OER the generated surface roughness and larger surface area can enhance OER activity of the catalyst. When used as a bifunctional electrocatalyst for overall water splitting, it can achieve a current density of 10 mA cm ‐2 at a cell voltage of 1.699 V with excellent durability. This work provides a new strategy to fabricate three‐dimensional heterostructured water‐splitting electrocatalysts with large surface area.

    更新日期:2020-01-16
  • Highly‐Healable Microsupercapacitors with Size‐Dependent 2D MXene
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-16
    Xingxing Li; Yanan Ma; Peizhi Shen; Chuankun Zhang; Jinfeng Yan; Yingbo Xia; Shijun Luo; Yihua Gao

    Very recently, 2D MXene has attracted a lot of attention in energy storage, due to its large specific surface area, good hydrophilicity, well conductivity and adjustable composition. Herein, we reported a kind of highly‐healable microsupercapacitors (MSCs) based on size‐dependent Ti3C2Tx MXene. Due to the rich physicochemical properties of Ti3C2Tx, the MSCs were fabricated by firstly spraying different lateral size MXene nanosheets onto the cellulose paper, and then selectively engraving interdigital electrodes by laser engraving machine. The flexible MXene‐based MSCs were assembled by sulfuric acid‐polyvinyl alcohol electrolyte. It is observed the electrochemical performance of MXene‐based MSCs is significantly affected by the nanosheet size. And the capacitance of MSCs fabricated by smaller lateral nanosheet reached up to 73.6 mF/cm2, which is higher than that of the larger lateral nanosheet and mixture one that contains smaller and larger nanosheets (1:1 mass ratio). Moreover, the self‐healable MXene‐based MSCs fabricated with polyurethane containing large number of hydrogen bonds as the wrapped material, present an excellent self‐healable ability with capacitance retention of 90% over 2000 charge/discharge cycles after 5th cutting/healing. And MXene‐based MSCs display great potential in the field of energy storage, which not only turn on the LED light but also drive the electronic clock.

    更新日期:2020-01-16
  • Photophysical and Electrochemiluminescence of novel coumarin‐based oxazaborines
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-15
    Tomáš Mikysek; Pavlos Nikolaou; Mirjeta Kafexholli; Petr Šimůnek; Jiří Váňa; Aneta Marková; Martin Vala; Giovanni Valenti

    We describe the synthesis, electrochemistry, photophysics, computational analysis and electrochemiluminescence (ECL) of a new series of oxazaborine molecules. Our strategy is based on the modification of coumarin‐oxazaborine moiety to be directly joined, through carbon‐carbon bond, and form donor–acceptor (D‐A) chromophores. These new structures substantially change the electron distribution as well as photophysical and electrochemical behavior with a strong effect on the final quantum yield. For all compounds, we observed a very high PL quantum yield (70− 75%) and relatively accessible first oxidation and first reduction. All these characteristics allows us to study the ECL of these molecules obtaining very high ECL efficiency, four times higher than the standard dyes, and opening the application of oxazaborine as bright ECL luminophores.

    更新日期:2020-01-15
  • On the influence of anion chaotropicity on the SO2 oxidation reaction: when spectator species determine the reaction pathway
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-15
    Andre Henrique Baraldi Dourado; Norberto Alves Silva-Jr.; Renan Lopes Munhos; Vinicius Del Colle; Matthias Arenz; Hamilton Varela; Susana Ines Cordoba de Torresi

    The electrochemical SO 2 oxidation reaction (SO 2 OR) is a promising alternative to the O 2 evolution reaction for H 2 electrochemical generation. The SO 2 OR exhibits a low thermodynamic potential and small kinetic barrier, and Au has been observed to be a very active catalyst. For this material, nonlinear dynamic behavior is observed, which is related to the electrolyte chaotropicity at the solid‐liquid interface. In this work, the influence of the chaotropicity was investigated by electrochemical and spectroelectrochemical techniques, and the main reasons for the dependence on the chaotropicity were investigated. The electrochemical response as a function of the chaotropicity was determined as a function of the mechanism observed, and the reaction pathway selection was related to the intermediate adsorption, which in turn was controlled by the interfacial water structure.

    更新日期:2020-01-15
  • Improving the Performance of SiOx/C Materials for High Energy Density Commercial Lithium Ion Batteries Based on Montmorillonite
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Lijuan Feng; Jimei Wang; Chao Sun; Fangfang Liu; Yuanzhong Wang

    Silicon is recognized as the most promising anode materials for the next generation battery. In order to improve the processing and electrochemical performances, a silicon‐based anode composite was synthesized using silicon, montmorillonite and carboxymethylcellulose (CMC) as raw materials. The processing parameters, such as particle size and specific surface, were ameliorated to be consistent with those of commercial lithium ion battery (LIB) anode materials. As an anode composite, it perfectly matched with high nickel ternary cathode materials and showed excellent electrochemical properties. The discharge capacities were all above 1000 mAh/g and the coulombic efficiency of each step was over 99% throughout the 50 cycles at 1 C (1100 mA/g). Its superior performances are attributed to the unique layered structure fabricated, which buffers the volume expansion and enhances the stability of the solid electrolyte interface (SEI) film on the anodic electrode, suggesting a perspective future in designing high energy density commercial LIBs.

    更新日期:2020-01-15
  • Hierarchical Porous Carbon Anode Materials Derived from Rice Husks with High Capacity and Long Cycling Stability for Sodium‐Ion Batteries
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Wei Nie; Xiaolin Liu; Qingmei Xiao; Liuxin Li; Guoxin Chen; Dong Li; Min Zeng; Shengwen Zhong
    更新日期:2020-01-14
  • CeO2 Encapsulated by Iron, Sulfur, and Nitrogen‐Doped Carbons for Enhanced Oxygen Reduction Reaction Catalytic Activity
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Mingjun Ji; Bing He; Yue Yu; Xiaodan Yu; Shuangxi Xing
    更新日期:2020-01-14
  • Branched sulfonated polyimide/sulfonated methylcellulose composite membrane with remarkable proton conductivity and selectivity for vanadium redox flow battery
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Jun Long; Hongyan Yang; Yanlin Wang; Wenjie Xu; Jun Liu; Huan Luo; Jinchao Li; Yaping Zhang; Hongping Zhang

    A series of branched sulfonated polyimide (bSPI)/ sulfonated methylcellulose (s‐MC) composite membranes composed of a designed and synthesized bSPI polymer and functionalized s‐MC are prepared by a facile solution casting method for vanadium redox flow batteries (VRFBs). Among all bSPI/s‐MC composite membranes, the optimized bSPI/s‐MC‐20% composite membrane has a proton selectivity of 2.45×105 S min cm‐3, which is 14.4 times as high as Nafion 115 membrane. The bSPI/s‐MC‐20% composite membrane possesses superior proton conductivity compared to most of reported SPI‐based composite membranes for VRFBs. The VRFB with bSPI/s‐MC‐20% composite membrane shows excellent battery efficiencies (CE=99.2‐98.0%, EE=66.3‐77.6%) and capacity retention (73.3‐47.2%). Moreover, the cost of bSPI/s‐MC‐20% composite membrane is only one‐fourth of that of commercial Nafion 115 membrane. This work develops a new strategy to fabricate cheap bSPI‐based composite membranes by introduction of a suitable functionalized biomass material.

    更新日期:2020-01-14
  • Unveiling Capacity Degradation Mechanism of Li‐ion Battery in Fast‐charging Process
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Sheng S. Zhang

    In this work, capacity degradation in fast‐charging process is studied by using a power‐optimized graphite‐LiNi0.80Co0.15Al0.05O2 (NCA) electrode couple and a three‐electrode coin cell as the testing vehicle. It is shown that capacity degradation consists of two distinct stages, (1) rapid degradation in early period and (2) progressive degradation over lifetime, which are associated with the electrochemical reduction of electrolyte solvents on the graphite anode and the structural deterioration of the NCA cathode, and are well correlated to a decrease in Coulomb efficiency. Analyses on the change in differential capacity profile and the recoverability of the lost capacity reveal that capacity degradation mainly originates from structural deterioration of the NCA cathode over lifetime, and it aggravates with the state‐of‐charge and temperature. Based on this guideline, we show that capacity degradation of the Li‐ion batteries in the fast‐charging applications can be greatly mitigated by limiting the cell’s operation to a relatively low state‐of‐charge (i.e., a relatively low charging cutoff voltage).

    更新日期:2020-01-14
  • Electroreduction of Oxygen on Carbide‐Derived Carbon Supported Pd Catalysts
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Madis Lüsi; Heiki Erikson; Ave Sarapuu; Maido Merisalu; Mihkel Rähn; Alexey Treshchalov; Päärn Paiste; Maike Käärik; Jaan Leis; Väino Sammelselg; Tiit Kaljuvee; Kaido Tammeveski

    Pd catalyst was deposited onto various carbide‐derived carbons (CDC) that were prepared from TiC, Mo 2 C and SiC. Specific surface area and pore size distribution of the Pd/CDC materials were measured. Microwave plasma assisted atomic emission spectroscopy was carried out to give information about the amount of Pd deposited. Scanning electron microscopy (SEM) studies revealed that CDC was uniformly covered by fine Pd particles, the size of which was further analysed by transmission electron microscopy (TEM). The oxygen reduction reaction (ORR) on Pd/CDC catalysts was studied in KOH and HClO 4 solutions. These electrocatalysts showed higher specific activities for ORR as compared to the commercial Pd/C.

    更新日期:2020-01-14
  • Dual‐Strategy to Construct Aqueous‐Based Symmetric Supercapacitors with High‐Volumetric Energy Density
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-14
    Li Zhang; Dandan Wu; Quanhu Ma; Gaowei Wang; Ziqiang Liu; Meixia Chang; Xingbin Yan

    Carbon‐based supercapacitors have been widely used in electric vehicles because of their high‐power density, long cycle life and fast charge/discharge rates. However, low volumetric energy density severely limits their application for miniaturized electronic devices. Here, we have demonstrated a carbon‐based symmetric supercapacitor by using a three‐dimensional porous graphene with high density as the electrode material and a 17 m NaClO 4 water‐in‐salt electrolyte with a 2.1 V electrochemical stability window. The device exhibited high specific capacitance (145.3 F cm −3 at 0.5 A g −1 ), excellent rate performance (70.0 % capacitance retention even at 50 A g −1 ), high volumetric energy density (22.3 Wh L −1 at 333.4 W L −1 based on the total mass of active materials) and excellent cycle stability with 99.1 % capacitance retention after 10,000 cycles at 5 A g −1 . The performance of this device was superior to the most current supercapacitors based on carbon materials. This effective dual‐strategy of simultaneously regulating capacitance and potential window can greatly promote the further development of aqueous carbon‐based supercapacitors.

    更新日期:2020-01-14
  • Study of the Ion Permeation through the Graphene Oxide/Polyether suflone Membranes
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-13
    Yongjing Zhang; Zhe Chen; Lei Yao; Xiao Wang; Qiuming Fu; Zhidong Lin; Shenggao Wang

    In this paper, the ion diffusion process through the graphene oxide (GO)/polyether sulfone(PES) membrane was probed by the electrochemical techniques. It was found that the GO/PES membrane exhibited lower rejection when feeding a solution with higher ion concentration. The calculated diffusion coefficient indicated that the Donnan repulsive interaction due to the GO platelets might play a key role in the rejection of GO/PES membrane. Computational calculation confirms that interlayer spacing shrinks less than 5% when increasing the solution concentration. These results suggest that compared with interlayer spacing, the Donnan repulsive interaction is more important for ion permeation during the concentration gradient‐driven diffusion. To investigate the detail of ion diffusion, electrochemical impedance spectroscopy (EIS) was utilized to probe the GO/PES membrane at initial immersing process. The EIS results showed an additional inductive loop at low frequency in the Nyquist plot at the initial diffusion stage, which would be more visible for the GO/PES membrane immersing at lower ion concentration. This inductive loop could be attributed to the uneven distribution of ions in GO/PES membrane, which is related to the cation‐adsorption capacity of GO.

    更新日期:2020-01-14
  • Overcoming Chemical Inertness under Ambient Conditions ‐ A Critical View on Recent Developments in Ammonia Synthesis via Electrochemical N2 Reduction by Asking Five Questions
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-13
    Qing Qin; Martin Oschatz

    Ammonia (NH 3 ) synthesis by the electrochemical N 2 reduction reaction (NRR) is increasingly studied and proposed as an alternative process to overcome the disadvantages of Haber‐Bosch synthesis by a more energy‐efficient, carbon‐free, delocalized, and sustainable process. An ever‐increasing number of scientists are working on the improvement of the faradaic efficiency (FE) and NH 3 production rate by developing novel catalysts, electrolyte concepts, and/or theoretical studies. This minireview provides a critical view on the interplay of different crucial aspects in NRR from the electrolyte, over the mechanism of catalytic activation of N 2 , to the full electrochemical cell. Five critical questions are asked, discussed and answered always coupled with a summary of recent developments in the respective field. This article is not supposed to be a complete summary of recent research about NRR but provides a rather critical view on the field. It is the major aim to give an overview over crucial influences on different length scales to shine light on the sweet spots into which room for revolutionary instead of incremental improvements may exist.

    更新日期:2020-01-13
  • Electrochemiluminescence of Glutathione‐Stabilized Au Nanoclusters Fractionated by Gel Electrophoresis in Water
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-13
    Yunjeong Kang; Joohoon Kim

    We report on electrochemiluminescence (ECL) of water‐soluble individual Au nanoclusters (Au NCs) fractionated by polyacrylamide gel electrophoresis of Au NCs synthesized using glutathione. The individual Au NCs possessed unique and significant differences in ECL. Interestingly, they exhibited near‐infrared (near‐IR) ECL that became dominant when the ratio of Au(I) to Au(0) decreased in the individual Au NCs. This indicated that the oxidation states of Au NCs primarily affected the ECL wavelengths of the clusters because the Au(0)‐glutathionate motif in the Au NCs was responsible for the near‐IR ECL emission.

    更新日期:2020-01-13
  • Electroless nano‐plating of Pd‐Pt alloy nanotube networks: Catalysts with full compositional control for the methanol oxidation reaction
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-10
    Tobias Stohr; Angelina Fischer; Falk Muench; Markus Antoni; Stephan Wollstadt; Christian Lohaus; Ulrike Kunz; Oliver Clemens; Andreas Klein; Wolfgang Ensinger

    Due to its simplicity, flexibility and conformity, electroless plating presents itself as an attractive route towards functional metal nanostructures. Despite the importance for creating multimetallic materials with enhanced properties, the complex interactions between the components in electroless plating baths make alloy formations a challenging objective. In this work, we outline an electroless plating strategy fabricating Pd‐Pt alloy nanomaterials, which is based on arbitrarily miscible plating baths for the individual metals. To demonstrate the excellent nanoscale conformity and homogeneity of our plating system, we apply it to ion track‐etched polymer templates with large inner surfaces as ambitious substrates, resulting in the formation of 3D free‐standing Pd x Pt 100‐x ‐nanotube‐networks (NTNWs). Based on the electro‐oxidation of methanol as a model reaction, we utilize the compositional freedom provided by our syntheses for optimizing the catalytic performance of our metal NTNWs, which heavily depends on the Pd‐Pt ratio. Within our system, the highest surface normalized activity was found for the Pd 20 Pt 80 ‐NTNW, reaching more than a two‐fold increase of the peak current density in comparison to pure Pt. Overall, our reaction system provides a versatile toolkit for fabricating intricate Pd‐Pt nanostructures of arbitrary elemental composition, and constitutes a starting point for designing new electroless alloy plating baths.

    更新日期:2020-01-11
  • Facile Synthesis of Nanoporous Au‐Cu‐Pt Alloy as Superior Catalyst for Methanol Oxidation Reaction
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-10
    Yunxiang Xie; Can Li; Sara A Razek; Jiye Fang; Nikolay G. Dimitrov

    Nanoporous (np) Au‐Cu‐Pt thin‐film catalyst with fine structure and tunable composition is synthesized using a facile method involving successive electrodeposition and de‐alloying. The catalyst’s structure, electronic state, elemental content, and active surface area along with the Pt fraction of it, are characterized and/or determined before and after methanol oxidation reaction (MOR) tests by electrochemical and ultrahigh vacuum analytical routines. The prepared np Au‐Cu‐(8% in the precursor alloy)Pt catalyst exhibits outstanding mass and specific activity toward MOR, which is approximately six‐ and nine‐times, respectively, higher than the activity of a commercial Pt/C(40%) counterpart. A negative 75 mV onset potential shift upon MOR anodic scan on the np Au‐Cu‐(8%)Pt catalyst in comparison with Pt/C(40%) corroborates its higher catalytic activity. Furthermore, the alloy catalyst demonstrates better durability than the Pt/C(40%) counterpart in a three‐hour constant potential test and exhibits full post‐factum recovery of its cycling activity. In addition, it retains more than 60% of its original activity after 3000 cycles of an accelerated degradation test. The outstanding performance is attributed to the specific catalyst’s structure leading to a d‐band upshift along with unique constituent interplay.

    更新日期:2020-01-11
  • Realizing superior cycle stability of a Ni‐rich layered LiNi0.83Co0.12Mn0.05O2 cathode with a B2O3 surface modification
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-09
    Qiang Li; Weidong Zhuang; Zhao Li; Shuaijin Wu; Ning Li; Min Gao; Wenjin Li; Jiantao Wang; Shigang Lu

    Ni‐rich cathode is considered a promising cathode for its high specific capacity. However, a sharp capacity attenuation induced by interface problems limits the application of the cathode material. Herein, we propose a practical surface modification strategy by introducing diboron trioxide (B 2 O 3 ) to the surface of LiNi 0.83 Co 0.12 Mn 0.05 O 2 (NCM) cathode materials. B 2 O 3 ‐modified NCM shows superior cyclic stability with a capacity retention of 87.7% at 1 C after 200 cycles in comparison to 69.4% for a bare NCM. On the basis of material and electrochemical characterizations, we conclude that the superior cycle stability of B 2 O 3 ‐modified NCM material benefits from the formation of B 2 O 3 coating and B 3+ doping on the surface. The B 2 O 3 coating layer that is confirmed by scanning and transmission electron microscopy can suppress surface side reactions and reduce the content of Li 2 CO 3 on the surface. The B 3+ ‐doping surface is verified by X‐ray diffraction and X‐ray photoelectron spectroscopy and triggers a reduction of a small amount of Ni 3+ to Ni 2+ . Furthermore, the combination of surface B 2 O 3 coating and B 3+ doping inhibits the irreversible phase transitions and extension of microcracks in the NCM material. The above surface modification strategy provides a direction for the acquisition of long‐life cathode materials.

    更新日期:2020-01-11
  • Facial synthesis of homogeneous hollow Co3O4 microspheres for enhanced cycle life and electrochemical energy storage performance
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-09
    Yaxiu Yang; Xin Chen; Yali Cao; Wanyong Zhou; He Sun; Hui Chai

    How to achieve a balance between excellent pseudocapacitive performance and simplicity of the synthetic pathway of Co 3 O 4 is still a challenge. Herein, hollow Co 3 O 4 microspheres were synthesized via a facile template‐free solvothermal approach with a following calcination treatment. The synthetic Co 3 O 4 exhibited remarkable electrochemical properties in terms of high specific capacity 922.7 F g ‐1 at 1 A g ‐1 , superior rate capability with 67.7% capacitance retention (1‐20 A g ‐1 ), as well as excellent cycling stability (105.6% retention after 10000 cycles). A hybrid supercapacitor device is also successfully assembled consisting of Co 3 O 4 cathode and rGO anode with a wide potential window of 0‐1.65 V and delivers a high energy density and an outstanding cycle lifetime. These superior electrochemical properties will render the hollow Co 3 O 4 microsphere material as an attractive material for promising application in high‐performance electrochemical energy storage systems.

    更新日期:2020-01-09
  • Array Microcell Method (AMCM) for Serial Electroanalysis
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-09
    Sasha E Alden; Natasha P Siepser; Jacqueline A Patterson; Gargi S Jagdale; Myunghoon Choi; Lane A Baker

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    更新日期:2020-01-09
  • Kinetics of Oxygen Reduction by a Beta Barrel Heme Protein on Hybrid Bioelectrodes
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-09
    Zahra Nazemi; Pallavi Prasad; Saumen Chakraborty

    Efficient catalysts are required to activate O2 at low overpotentials with improved reaction kinetics. The kinetics of electrocatalytic oxygen reduction by a b‐barrel, the nitrobindin heme protein (NBHP) is investigated using protein‐film electrochemistry. Structure‐guided strategies were developed to covalently attach NBHP and enable efficient interfacial electron transfer (ET) between the protein and electrode. The reduction of Fe(III) to Fe(II) with rate constant ks of 25 s‐1 is invoked as the rate limiting step of the catalytic process, as opposed to a proton‐coupled electron transfer (PCET) process. Further kinetic analyses revealed a complete 4e‐ reduction of O2 to H2O at lower pH, attributable to a higher H+ availability and more facile reduction of the heme in acidic conditions compared to the basic conditions where an incomplete 2e‐ reduction to H2O2 was observed. The rate constants kORR, k0, and the turnover numbers demonstrate that NBHP is an efficient biocatalyst for O2 electrolysis.

    更新日期:2020-01-09
  • Electrochemical Analysis of the Mechanism of Potassium‐Ion Insertion into K‐rich Prussian Blue Materials
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-08
    Eduard E. Levin; Aleksandr A. Kokin; Denis E. Presnov; Andrei G. Borzenko; Sergey Yu. Vassiliev; Victoria A. Nikitina; Keith J. Stevenson

    The electrochemical insertion patterns of potassium‐rich Prussian blue materials with different compositions and particle sizes were systematically compared which allows deducing correlations on the influence of particle morphology and material structure on the potassium‐ion insertion mechanisms in aqueous solutions. While the structural analysis indicates that no first‐order phase transitions occur for nanosized K‐rich Prussian blue particles upon potassium‐ion (de)insertion, the electrochemical data (galvanostatic charge/discharge, cyclic voltammetry, small‐ and large‐amplitude potential step experiments) suggest other outcomes related to the two‐phase insertion mechanism for all the explored PB samples. However, even in the case when the phase transformation is not accompanied by abrupt changes in the crystal structure, the two‐phase mechanism dominates all the essential practical characteristics of performance of this cathode material, such as hysteresis (overpotential) between charge and discharge steps and the measured diffusivities of potassium‐ions during charge and discharge. The formulism presented herein provides a basis for quantitatively assessing ion insertion and deinsertion parameters unique to Prussian blue analogues.

    更新日期:2020-01-09
  • 更新日期:2020-01-08
  • A novel composite CoFe2O4@CSs as electrode by easy one‐step solvothermal for enhancing the electrochemical performance of hybrid supercapacitors
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-08
    Ahmed Mourtada Elseman; Moataz G. Fayed; Saad G. Mohamed; Deiaa A. Rayan; Nageh. K. Allam; Mohamed M. Rashad; Qunliang Song

    Constructing electrode materials with high energy densities are the effective way to develop asymmetric supercapacitor devices. Therefore, the inlay of conductive materials into pseudo‐capacitive constituents is a practical approach to increase the performance of supercapacitors electrodes. Herein, we declare a facile one‐step as an economic strategy for tailoring of carbon spheres (CSs) impregnated by CoFe2O4 to form CoFe2O4@CSs composite. The composite CoFe2O4@CSs was fully characterized by X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), which evinced that CoFe2O4 nanoparticles were densely and cored inside carbons spheres. Moreover, the electrochemical characterization of CoFe2O4@CSs composite was manifested high specific capacitance of (600 F/g) at a current density (1 A/g), high‐performance rate, and cycling stability. CoFe2O4@CSs has achieved capacitance retentions of 94.1% after 5000 charge/discharge cycles at a current density of 20 mA/g. The device based asymmetric supercapacitors was found to improve the energy density with 27.08 Wh/kg at a power density of 750 W/kg with 99 % capacitance retention which was higher than the previously reported. The exceptional performance of CoFe2O4@CSs composites gives high priority for such materials in variant electrochemical fields due to the wonderful harmony impacts between CoFe2O4 nanoparticles and carbon spheres.

    更新日期:2020-01-08
  • Plasma‐enabled ternary SnO2@Sn/nitrogen‐doped graphene aerogel anode for sodium‐ion batteries
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-08
    Yujie Ma; Qianqian Wang; Li Liu; Shuyue Yao; Wenjie Wu; Zhongyue Wang; Peng Lv; Jiajin Zheng; Kehan Yu; Wei Wei; Kostya (Ken) Ostrikov

    SnO 2 ‐based sodium‐ion batteries usually suffer from rapid capacity fading during the sodiation/desodiation caused by aggregation and cracking of Sn and irreversible formation of Na 2 O. To this respect, we design a ternary SnO 2 @Sn core‐shell structure decorated on nitrogen‐doped graphene aerogel (SnO 2 @Sn/NGA) which is fabricated by a microwave plasma based process. The converted Na 2 O can prevent agglomeration of Sn, thus stabilizing the structure during the cycles. Close contact between Na 2 O and Sn ensures Na + ion diffusion to the Sn core and reversible conversion Sn Common.EditSubmissionSteps.Transform.EquationText SnO 2 . Moreover, the deoxygenation effect of the plasma on NGA improves its degree of graphitization and electrical conductivity, which substantially improves the electrode rate performance. As a result, the SnO 2 @Sn/NGA anode delivers a high initial discharge capacity of 448.5 mAh g ‐1 at 100 mA g ‐1 . Importantly, this unique nanohybrid electrode design can be extended to advanced anode materials for both lithium‐ and sodium‐ion batteries.

    更新日期:2020-01-08
  • Electrochemistry for Life Detection on Ocean Worlds
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-07
    Seamus D. Thomson; Richard C. Quinn; Antonio J. Ricco; Jessica E. Koehne
    更新日期:2020-01-07
  • Optimization of Electrode Potential Ranges for Constructing 4.0 V Carbon‐Based Supercapacitors
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-07
    Meng Ye; Hongwei Guo; Qingyun Dou; Hui Guo; Ruilin Hou; Junhong Guo; Xingbin Yan
    更新日期:2020-01-07
  • Hollow Spheres Consisting of SnS Nanosheets Conformally Coated with S‐Doped Carbon for Advanced Lithium‐/Sodium‐Ion Battery Anodes
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-07
    Weiyuan Guo; Kang Ding; Shixiong Mei; Xingxing Li; Xiaoyu Feng; Siguang Guo; Jijiang Fu; Xuming Zhang; Biao Gao; Kaifu Huo; Paul K. Chu
    更新日期:2020-01-07
  • 更新日期:2020-01-07
  • A Combined Theory‐Experiment analysis of the Surface Species in Lithium Mediated NH3 Electrosynthesis
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-07
    Jay A. Schwalbe; Michael J. Statt; Cullen Chosy; Aayush R. Singh; Brian A. Rohr; Adam C. Nielander; Suzanne Z. Andersen; Joshua M. McEnaney; Jon G. Baker; Thomas F. Jaramillo; Jens K. Norskov; Matteo Cargnello

    Electrochemical processes for ammonia synthesis could potentially replace the high temperature and pressure conditions of the Haber‐Bosch process with voltage, offering a pathway to distributed fertilizer production that leverages the rapidly decreasing cost of renewable electricity. However, nitrogen is an unreactive molecule and the hydrogen evolution reaction (HER) presents a major selectivity challenge. An electrode of electrodeposited lithium in tetrahydrofuran solvent overcomes both problems by providing a surface that easily reacts with nitrogen and by limiting the access of protons with a nonaqueous electrolyte. Under these conditions, we measure relatively high faradaic efficiencies (~10%) and rates (0.1 mA cm ‐2 ) toward NH 3 . We observe development of a solid electrolyte interface (SEI) layer as well as the accumulation of lithium and lithium‐containing species. Detailed DFT studies suggest lithium nitride and hydride to be catalytically active phases given their thermodynamic and kinetic stability relative to metallic lithium under reaction conditions and the fast diffusion of nitrogen in lithium.

    更新日期:2020-01-07
  • Experimental, simulation and computational study of the interaction of reduced forms of N‐methyl‐4,4’‐bipyridinium with CO2
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-07
    Daniel Buttry; Poonam Singh; Pilarisetty Tarakeshwar

    N‐methyl‐4,4’‐bipyridinium (Mebipy+) can be reduced in two separate one electron steps in 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI). The first reduction product Mebipy, a radical species, is shown to have no significant interaction with dissolved CO2. In contrast, the second reduction product, Mebipy‐, forms an adduct with CO2. This adduct has a relatively strong C‐N bond from nucleophilic interaction of the non‐quaternized nitrogen of the anion with the electrophilic carbon of CO2. These interactions are characterized using density functional theory (DFT). During electrochemical reduction of Mebipy+ in the presence of dissolved CO2, this strong interaction of Mebipy‐ drives a disproportionation reaction in which two Mebipy radicals react to produce Mebipy+ and Mebipy‐, which subsequently reacts with CO2 to form the nitrogen‐bound adduct, Mebipy‐CO2‐, a type of carbamate. This electrochemical DISP mechanism is simulated, providing a good fit with experimental results. The overall stoichiometry for the electrochemical capture and release of CO2 in this system is that two electrons are required to bind one equivalent of CO2.

    更新日期:2020-01-07
  • Excellent rate and low temperature performance of lithium ion batteries based on binder‐free Li4Ti5O12 electrode
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-06
    Bingqing Hu; Xiaoshuang Zhou; Jiang Xu; Xi Wang; Ningyi Yuan; Shanhai Ge; Jianning Ding

    Achieving lithium ion batteries (LIBs) with ultrahigh rate at ambient‐temperature and excellent low temperature‐tolerant performances is still a tremendous challenge. In this paper, we design a binder‐free Li 4 Ti 5 O 12 (LTO) electrode to achieve an excellent rate performance (~75 % of its theoretical capacity at 200 C), in which, aligned CNT nanosheets were used to load LTO nanosheets decorated with silver nanocrystals. With combination of 1,3‐Dioxlane‐based electrolyte, there is nearly no initial voltage drop happen, and the capacity can be greater than 140 mAh g ‐1 (~85 % of its specific capacity at room temperature) at ‐60 °C and 0.2 C. This study provides a practical guidance of the design of LIBs with outstanding rate performances and low temperature resistance.

    更新日期:2020-01-07
  • 更新日期:2020-01-04
  • Clostridium Acetobutylicum’s Connecting World: Cell Appendage Formation in Bioelectrochemical Systems
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    Mareike Engel; André Gemünde; Dirk Holtmann; Christine Müller‐Renno; Christiane Ziegler; Nils Tippkötter; Roland Ulber
    更新日期:2020-01-04
  • High‐Performance Flexible Asymmetric Supercapacitors Facilitated by N‐doped Porous Vertical Graphene Nanomesh Arrays
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    Kai Chi; Xiangyu Zhang; Xin Tian; Zheye Zhang; Zhu Wu; Fei Xiao; Shuai Wang
    更新日期:2020-01-04
  • High‐Performance Flexible Asymmetric Supercapacitors Facilitated by N‐doped Porous Vertical Graphene Nanomesh Arrays
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    Kai Chi; Xiangyu Zhang; Xin Tian; Zheye Zhang; Zhu Wu; Fei Xiao; Shuai Wang
    更新日期:2020-01-04
  • Effect of Experimental Operations on the Limiting Current Density of Oxygen Reduction Reaction Evaluated by Rotating Disk Electrode
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    Guoyu Zhong; Shurui Xu; Lei Liu; ChengZhi Zheng; Jingjing Dou; Fengye Wang; Xiaobo Fu; Wenbo Liao; Hongjuan Wang

    The universal linear scan voltammogram measurement on the rotating disk electrode (RDE) has been identified as a simple method to investigate the oxygen reduction activity of electrocatalysts. The steady‐state limiting current density I lim indicates the maximum diffusion current density in the oxygen reduction reaction (ORR) during RDE measurement, which should be a fixed value in theory for a 4e ORR in a particular concentration solution and at a certain rotate speed. However, in experiments, I lim is always variable and smaller than theoretical value even though with the same the catalyst, electrode, and rotator. So the impact of various experimental operating parameters on I lim is highly necessary to be investigated. In this paper, factors, such as catalyst loading, O 2 inlet condition, O 2 flow rate, gas tightness, solution concentration, and purity, have been investigated for their effects on the I lim of ORR on three typical catalysts (20% commercial Pt/C, Iron/Nitrogen/Carbon‐catalyst and N‐doped carbon nanotubes). The results indicate that the catalyst loading and O 2 inlet condition are the key factors influencing the I lim of ORR. While, the O 2 flow rate, gas tightness, solution concentration, and purity have little influence on the I lim of ORR. The correct I lim could be obtained under the optimized catalyst loading and the O 2 inlet with an extended sand core tube.

    更新日期:2020-01-04
  • AgCoO2 ‐Co3O4/CMC Cloudy Architecture as High Performance Electrodes for Asymmetric Supercapacitor
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    I. Manohara Babu; J. Johnson William; G. Muralidharan

    This work represents the design of superior supercapacitor electrode that comprised of 3D cloud like silver cobalt oxide/cobalt oxide (AgCoO2‐Co3O4) and carbon architecture. AgCoO2‐Co3O4/C architecture can be fabricated from Co‐Ag nitrate precursors with the addition of carboxymethyl cellulose followed by annealing. Mesoporous 3D cloudy architecture provides higher specific capacitance (575 F g‐1 at a scan rate of 2 mV s‐1) and rate performance (666 F g‐1 at a current density of 1 A g‐1). The combined effect of AgCoO2 embedded Co3O4 and carboxymethyl cellulose (carbon) highly favours for outstanding cycle life (around 1 % capacitance degradation even after 5000 cycles). Presence of such porous 3D architecture with carbon backbone delivers admirable energy/power density. Also, an advanced asymmetric supercapacitor with an operating range of 1.2 V is designed by utilizing this porous 3D cloudy architecture as positive electrode and activated carbon as negative electrode. The fabricated design shows a robust energy density of 17 W h kg‐1 with a high power density of 166 W kg‐1 at a current density of 1 A g‐1. The findings of the current study underline the potential of AgCoO2‐Co3O4/C electrodes for supercapacitor applications.

    更新日期:2020-01-04
  • Maximized Energy Density of RuO2//RuO2 Supercapacitors through Potential Dependence of Specific Capacitance
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-03
    Yilun Wang; Dawei Gu; Jiaren Guo; Mingyang Xu; Hongshun Sun; Jishu Li; Lei Wang; linjiang shen

    In this study, a piecewise cyclic voltammetry approach was proposed to clarify the potential dependence of specific capacitance for reduced graphene oxide and ruthenium oxide electrodes. Based on the relationship between specific capacitance and potential, the working voltage window and energy density of RuO 2 //RuO 2 supercapacitor (SC) were maximized by modulating the mass ratio. The working voltage window of RuO 2 //RuO 2 with mass ratio of 2.03 (close to optimum mass ratio ) was extended by about 188% when compared to that calculated at mass ratio of 0.56. The former was equivalent to 304% increment in energy density. In addition, the source of wasted potential window of electrodes on RuO 2 //RuO 2 was investigated in an effort to design and produce better SCs.

    更新日期:2020-01-04
  • Titanium as a Novel Substrate for Three‐Dimensional Hybrid Electrodes for Vanadium Redox Flow Battery Applications
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-02
    Xubin Lu; Fan Li; Matthias Steimecke; Muhammad Tariq; Mark Hartmann; Michael Bron

    Titanium, either in form of a Ti foil or in form of a Ti mesh, was used as a novel substrate to grow nitrogen‐doped carbon nanotubes (NCNTs) by chemical vapor deposition at moderate temperatures over electrodeposited iron particles. The thus‐prepared high‐surface‐area electrodes where characterized using scanning electron microscopy (SEM), Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The electrochemical performance towards the V(IV)/V(V) redox couple was investigated using cyclic voltammetry. The parameters for iron particle electrodeposition were adjusted towards high and uniform substrate coverage. Nanotube growth from acetonitrile at moderate temperatures (600 °C) led to N‐containing CNTs with a high amount of graphitic nitrogen. NCNTs grown over Ti substrates provide promising performances towards the V(IV)/V(V) as well as the V(III)/V(IV) redox pair. In general, the results of this study show that Ti might be a suitable electrocatalyst substrate for various applications in electrochemical energy conversion.

    更新日期:2020-01-02
  • Improving Gating Efficiency of Electron Transport through Redox‐active Molecular Junctions with Conjugated Chain
    ChemElectroChem (IF 3.975) Pub Date : 2020-01-02
    Fan Zhang; Xiao-Hui Wu; Yi-Fan Zhou; Ya-Hao Wang; Xiao-Shun Zhou; Yong Shao; Jian-Feng Li; Shan Jin; Ju-Fang Zheng

    Tuning the electron transport at molecular scale is a key step to realize functional electronic components in molecular electronics, and ongoing interest is to achieve a higher modulation ratio for single‐molecular transistor. Here, a feasible strategy that connecting the redox‐active moieties with conjugated chains was proposed to improve the electrochemical gating efficiency of molecular junctions in ionic liquid. Benefiting from the low energy barrier height between Fermi level of electrode and frontier molecular orbitals, the conductance of C=C‐Fc‐Py shows about one order of magnitude larger and 160% improvement of conductance on/off ratio compared to that of C‐C‐Fc‐Py at the equilibrium potential of Fc + /Fc. This work provides a new way to design a high performance of molecular devices.

    更新日期:2020-01-02
  • Single‐Site, Single‐Metal‐Atom, Heterogeneous Electrocatalyst: Metal−Organic‐Framework Supported Molybdenum Sulfide for Redox Mediator‐Assisted Hydrogen Evolution Reaction
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-31
    Hyunho Noh; Ying Yang; Xuan Zhang; Timothy A Goetjen; Zoha H Syed; Zhiyong Lu; Sol Ahn; Omar K Farha; Joseph T. Hupp

    Synthesis of single‐site catalysts whereby the local structure and the surrounding chemical environment are identical has been challenging particularly in heterogeneous catalysis as the support often presents spectrum of chemically distinct binding sites. Yet, the above criteria are crucial in attributing the apparent catalytic performance to the structural motif. The presented work augments on our previous work using monometallic molybdenum sulfide tethered within a zirconium‐based metal−organic framework (MOF), NU‐1000; the monometallic nature enables all presented sites to be catalytically addressable. As the molybdenum sulfide species resided within two distinct pores (micro‐ and mesopores) of the MOF support, we have imparted uniformity in the local chemical environment by reducing the pore heterogeneity down to a single mesopore. Single‐site and single‐atom nature of the candidate catalyst was established via X‐ray diffraction measurements. Redox mediators were implemented, which under a reductive potentials, provide reduced species; they can effectively deliver the necessary reducing equivalences to the catalytic units otherwise electrochemically unaddressable due to the low electron mobility within the framework. Our results indicate the micropore‐allocated molybdenum sulfide is ca. four times more active as to that in mesopores, while its catalytic mechanism is identical, underscoring the importance of controlling chemical environment beyond the active site.

    更新日期:2020-01-01
  • Improving Lithium–Metal Battery Performance under Lean Electrolyte through MoS2 Coating
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-30
    Eunho Cha; Hongkyung Lee; Wonbong Choi

    Although lithium‐metal based batteries (LMBs) offer one the highest energy densities, the issues with Li dendrite growths and the chemical reactivity between Li and electrolytes limit their applications. To enable a stable LMB under the practical conditions of lean electrolyte, thin Li‐metal and high mass loading, we introduce an efficient protective coating of MoS 2 onto Li‐metal anode and analyzed its electrochemical performance under the practical condition. The MoS 2 coating successfully stabilizes the chemical activity of Li‐metal surface by preventing dendrite growths and electrolyte dry‐out, which results in the enhanced Li‐metal battery cycle life by three‐fold under the stringent condition.

    更新日期:2019-12-31
  • Electrochemical oxidation of glycine by bimetallic nickel‐manganese oxide catalysts
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-30
    Roopathy Mohan; Arindam Modak; Alex Schechter; Rivka Cahan; Aharon Gedanken; Palaniappan Subramanian; P. Sivakumar

    A simple template‐free hydrothermal route followed by high temperature (800 °C) annealing in air forms Ni‐Mn bimetallic oxides, namely NiMn 2 O 4 , Ni 1.5 Mn 1.5 O 4, MnNi 2 O 4 and are characterized by XRD, Raman, EDS, and SEM analysis. Electrocatalytic activity of these metal oxides toward the oxidation of glycine molecules in alkaline condition was studied by cyclic voltammetry and linear sweep voltammetry methods. Among other nickel manganese bimetallic oxides and monometallic oxides (Mn 2 O 3 , NiO), Ni 1.5 Mn 1.5 O 4 shows excellent redox characteristics with high oxidation current density (310 µA.cm ‐2 at 0.43 V vs. Ag/AgCl) and lower onset potential (0.22 V vs. Ag/AgCl). Additionally, Ni 1.5 Mn 1.5 O 4 exhibits moderate Tafel slope (78 mV.dec ‐1 ) and is electrochemically stable as confirmed from chronoamperometry, indicating its potential for glycine oxidation. The linear dependence of the oxidation current with glycine concentration is signifying that the overall process is diffusion controlled. The electrochemical results suggest that bimetallic mixed Mn and Ni oxides are promising glycine oxidation catalyst, which may be attributed to the cooperative effect between different Ni and Mn elements.

    更新日期:2019-12-30
  • Carbon/inorganic hybrid nanoarchitecture as carrier for signaling in electrochemical immunosensors. First biosensor for inflammatory and metastatic processes biomarker RANK‐ligand
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-30
    Paloma Yáñez-Sedeño; Alejandro Valverde; Verónica Serafín; Ana Montero-Calle; Araceli González-Cortés; Rodrigo Barderas; Susana Campuzano; José M Pingarrón

    This work reports the development of the first integrated electrochemical immunosensor for the determination of the ligand receptor activator nuclear factor‐κB (RANKL), a biomarker that plays an important role in the regulation of bone resorption process and, as reported recently, in oncology by modulating the immune system response facilitating the tumor growth and metastatic process during cancer development. The developed platform involves a sandwich‐type immunoassay with covalent immobilization of biotinylated capture antibodies onto streptavidin/4‐aminobenzoic acid ( p ‐ABA) grafted screen‐printed carbon electrodes (bCAb‐Strep/ p ‐ABA‐SPCE) and the use of an hybrid nanomaterial composed of gold nanoparticles (AuNPs) and multi‐walled carbon nanotubes (MWCNTs) as nanocarrier of multiple detector antibody and HRP molecules. Amperometric detection with the H 2 O 2 /hydroquinone (HQ) system allowed the construction of a linear calibration plot for RANKL standards between 10.4 and 1,000 pg mL ‐1 with a LOD of 3.1 pg mL ‐1 . The determination implied simple handling protocols and short assay times. The developed immunosensor was applied to the determination of RANKL in human serum of patients diagnosed with colorectal cancer (CRC) or rheumatoid arthritis (RA). Each determination required only 5 μL of undiluted serum and took less than 2 h counting since the preparation of blocked‐bCAb‐Strep/ p ‐ABA‐SPCE.

    更新日期:2019-12-30
  • Electrooxidation, Size Stability, and Electrocatalytic Activity of 0.9 nm Diameter Gold Nanoclusters Coated with a Weak Stabilizer
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-30
    Francis Patrick Zamborini; Dhruba Pattadar; Badri Mainali

    Here we describe the electrooxidation and size stability of 0.9 nm average diameter triphenylphosphine monosulfonate (TPPS)‐stabilized Au nanoclusters (NCs) as compared to 1.6 nm tetrakis(hydroxymethyl)phosphonium chloride (THPC)‐stabilized Au NCs and 4.1 nm citrate (Cit)‐stabilized Au nanoparticles (NPs). The potential for oxidative dissolution in KBr follows the order of TPPS Au0.9nm NCs (0.219 V) < THPC Au1.6nm NCs (0.452 V) < Cit Au4.1nm­ NPs (0.723 V) < bulk Au (~0.932 V) while that for surface Au oxide reduction follows the order of TPPS Au0.9nm NCs (0.607 V) < THPC Au1.6nm NCs (0.679 V) < Au4.1nm NPs (0.808 V) vs. Ag/AgCl. TPPS Au0.9nm NCs and Cit Au4.1nm NPs convert to larger aggregates by fusing together in acidic pH, while THPC Au1.6nm NCs are highly stable from pH 2.4‐11. Exposure of TPPS Au0.9nm NCs to ozone causes considerable size increase within 1‐2 minutes, similar to previous results on THPC Au1.6nm. THPC Au1.6nm NCs are stable against oxidation after exchange of THPC with 1‐butanethiol while TPPS Au0.9nm NCs dissolve into solution during exchange. TPPS Au0.9nm NCs are inactive for the hydrogen evolution reaction and CO2 reduction reaction, whereas THPC Au1.6nm NCs exhibit excellent activity. The differences in oxidation potential, size instability, and electrocatalytic activity are due to the Au size as opposed to the different ligands, while the pH‐induced aggregation depends on the acidic or basic nature of the stabilizing ligand.

    更新日期:2019-12-30
  • Highly loaded mildly edge‐oxidized graphene nanosheet dispersions for large‐scale inkjet printing of electrochemical sensors
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-29
    Bhawna Nagar; Milica Jović; Victor Costa Bassetto; Yingdi Zhu; Horst Pick; Pedro Gómez-Romero; Arben Merkoçi; Hubert H Girault; Andreas Lesch

    Inkjet printing of electrochemical sensors using a highly loaded mildly edge‐oxidized graphene nanosheet (EOGN) ink is presented. An ink with 30 mg/mL EOGNs is formulated in a mixture of N‐methyl pyrrolidone and propylene glycol with only 30 min of sonication. The absence of additives, such as polymeric stabilizers or surfactants, circumvents reduced electrochemical activity of coated particles and avoids harsh post‐printing conditions for additive removal. A single light pulse from a xenon flash lamp dries the printed EGON film within a fraction of a second and creates a compact electrode surface. An accurate coverage with only ⁓30.4 µg of EOGNs per printed layer and cm 2 is achieved. The EOGN films adhere well to flexible polyimide substrates in aqueous solution. Electrochemical measurements were performed using cyclic voltammetry and differential pulse voltammetry. An all inkjet‐printed three‐electrode living bacterial cell detector is prepared with EOGN working and counter electrodes and silver‐based quasi‐reference electrode. The presence of E. coli in liquid samples is recorded with four electroactive metabolic activity indicators.

    更新日期:2019-12-30
  • Green Synthesis of Pyridyl Conjugated Microporous Polymers as Precursors for Porous Carbon Microspheres for Efficient Electrochemical Energy Storage
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-28
    Yaozu Liao; Yan He; Zhonghua Cheng; Hongyu Zuo; Chunna Yan

    Efficient materials for electrochemical energy storage have received much attention. Herein we report a green metal‐free route to synthesize pyridyl conjugated microporous polymers (PCMPs) as precursors for nitrogen‐doped porous carbon microspheres (NCMs) with high surface areas up to 1232 m2 g‐1 via a simple carbonization method. The resulting NCMs as supercapacitive electrodes exhibit high specific capacitance of 324 F g‐1 at a current density of 0.1 A g‐1, and high rate ability (182 F g‐1 at 10 A g‐1), and excellent cyclability (remained >97% of initial capacitance at 2 A g‐1 after 10000 cycles). This work also presents that molecular engineering of PCMP precursor, pyrolysis temperature and charge/discharge cycling allow the electrochemical energy storage properties of the NCMs to be controlled.

    更新日期:2019-12-29
  • An amplified electrochemical aptasensor for sialic acid based on carbon cloth‐supported Au nanodendrites and functionalized Au nanoparticles
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-27
    Yubing Lv; Yanli Zhou; Hui Dong; Lantao Liu; Guoliang Mao; Yintang Zhang; Maotian Xu

    The abnormal expression of sialic acid (SA) on the cell surface or in body fluids has been proven to correlate with several diseases. An electrochemical approach has been developed for sensitive and accurate determination of SA in human serum samples. Gold nanodendrites (AuNDs) electrodeposited on a carbon cloth (CC) electrode were utilized as the substrate electrode and provided high surface area and conductivity. The thiolated nucleic acid aptamer of SA was immobilized and recognized SA specifically, followed by the attachment of the nanocomposite of gold nanoparticles with 4‐mercaptophenylboric acid and thionine (MPBA‐AuNP‐Th) via boronic acid‐diol binding. An amplified signal by the electrochemical reduction of Th could be obtained because of high conductivity of substrate and high loading of Th on AuNPs. The proposed sensor exhibited remarkable selectivity and high sensitivity with a low detection limit of 60 nM due to the high affinity of aptamer and the signal amplification strategy, respectively. The feasibility of the aptasensor was verified by evaluation of SA level in human serum.

    更新日期:2019-12-29
  • 更新日期:2019-12-27
  • Surface Properties of Battery Materials Elucidated Using Scanning Electrochemical Microscopy: The Case of Type I Silicon Clathrate
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-27
    Tsvetan Tarnev; Patrick Wilde; Andrew Dopilka; Wolfgang Schuhmann; Candace K. Chan; Edgar Ventosa
    更新日期:2019-12-27
  • Design ultra‐microporous carbons with pore size of 0.6 nm dominant by interpenetrating MF prepolymer into PAAS networks at molecule level for enhanced electrochemical performances
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-25
    Yan-Dong Ma; Jian-Fei Gao; Xi-Wen Chen; Ling-Bin Kong

    The pore structure control of porous carbons, especially ultra‐microporous carbons, has long been a great challenge, and it is desirable to propose new strategies to deal with this dilemma. Herein, we designed and obtained ultra‐microporous dominant porous carbon materials (UMC‐IPNs) with an unimodal pore diameter of 0.6 nm by the strategy of interpenetrating polymer networks precursor carbonization. Thanks to the intertwining characteristics of the two interpenetrating polymer networks, the microphase separation which often occurs between the polymers is well suppressed, and also the pores of the as‐obtained ultra‐microporous carbons are interconnected. The calculated specific surface area is 1551 m2 g‐1. Furthermore, as electrode material, UMC‐IPNs has been confirmed to have exceptional electrochemical performance (the specific capacitance is 268 F g‐1 at 0.5 A g‐1, and after 10,000 cycles, the capacity is 96% of the original at 6 A g‐1) and rapid electrochemical kinetics (the surface capacitance effect ratio is about 85.4% in our calculation results). In addition, ultra‐microporous carbons are interesting for other applications such as gas capture, catalyze, and sensor technology.

    更新日期:2019-12-27
  • MoS2 nanosheets coupling Ni2P hollow microspheres as an efficient electrocatalyst for hydrogen generation over a wide pH range mediated by 3D/2D interface
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-25
    Caiyan Gao; Zhuoqian Li; Haiyang Wang; Yaqi Yang; Baojun Li; Zhikun Peng; Jun Li; Zhongyi Liu

    Developing high activity, strong durability and cost‐efficient electrocatalyst for hydrogen evolution reaction (HER) is critical for the sustainable production of hydrogen energy. Herein, we have rationally designed a three‐dimensional (3D) hollow nickel phosphide spheres coupling molybdenum sulfide nanosheets heterogeneous catalyst (Ni 2 P@MoS 2 ). Benefiting from the hollow spherical structure and the coupling effects between MoS 2 and Ni 2 P, the Ni 2 P@MoS 2 shows superior activity for hydrogen generation over a wide pH range. It displays overpotentials of 181, 269 and 535 mV in 1.0 M KOH, 0.5 M H 2 SO 4 and 1.0 M PBS at current density of 10 mA cm ‒2 , respectively. A series of characterizations demonstrate that the strong coupling interaction between Ni 2 P and MoS 2 effectively optimize the electronic structure of the Ni 2 P‐MoS 2 3D/2D interfaces, benefiting for regulating H* adsorption energy. This work offers a novel strategy for enhancing the HER performance of metal phosphide/sulfide catalysts via constructing heterostructural materials with abundant 3D/2D interfaces.

    更新日期:2019-12-27
  • CdS Quantum Dots‐Organometallic Halide Perovskites Bilayer Electrodes Structures for Supercapacitor Applications
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-25
    Luqman E. Oloore; Mohammed Ashraf Gondal; Idris. K. Popoola; AbdulJelili Popoola

    Supercapacitors are attracting great attention because of their fast charging−discharging ability as well as high power density. The current research in this area focuses mainly on exploring novel low‐cost electrode materials with higher energy and power densities. In this work, thin film electrochemical capacitors were fabricated using layers of self‐synthesized cadmium sulfide quantum dots and bulk organometallic halide perovskite materials as active electrodes. Organometallic halide perovskites exhibit interesting ionic responses besides its extraordinary electronic property. These properties are exploited in fabricating the electrochemical capacitors and the devices show excellent cyclability with stable capacitance output beyond 4000 cycles. Impedance spectroscopy measurements revealed that perovskites do not only serve as active electrodes but also as solid electrolytes thereby enhancing capacitance of the devices and hence energy densities. The layers provide high surface area for electrolytes to access the electrode materials; reasonably low charge transfer resistance and small relaxation time were also observed. This work opens new opportunities for developing thin film supercapacitors using low‐cost electrode materials and employing a facile, inexpensive solution process coating.

    更新日期:2019-12-26
  • MOF‐Nanorod‐doped Solid Polymer Electrolyte with Decreased Crystallinity for High Performance All‐solid‐state Lithium Battery
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-24
    Zheng Zhang; Jin-Hai You; Shao-Jian Zhang; yao zhou; Chuan-Wei Wang; Jun-Tao Li; Ling Huang; Shi-Gang Sun

    Poly (ethylene oxide) (PEO) as an important solid polymeric electrolyte (SPE) for solid‐state lithium batteries suffers from low ionic conductivity and poor electrochemical stability; many inorganic solid compounds have been explored as fillers to address these issues. Herein, we report that Al‐MOF nanorods could work as efficient solid fillers to boost the electrochemical performance of the PEO‐based SPEs. The addition of MOF nanorods was found to inhibit the crystallization of PEO and weaken the interactions among the PEO chains effectively, resulting in evidently enhanced ionic conductivity and improved electrochemical stability; moreover, when embedded in the PEO, such Al‐MOF nanorods are microporous and micrometer long, which are expected to favor the transportation of Li+ over the significantly more bulky anions TFSI‐. Compared with the pure PEO SPE, our optimal sample PEO‐MOF5% SPE has obviously higher ion conductivity (2.09×10‐5 S/cm at 30 ºC and 7.11×10‐4 S/cm 60 ºC), larger lithium ion transference number (0.46) and enlarged electrochemical window (4.7 V versus Li/Li+). Accordingly, the cell of LiFePO4/PEO‐MOF5%/Li shows excellent cycle performance and rate performance. Our work proved the advantages of MOF particles as solid fillers towards high performance PEO‐based SPE, and we also for the first time put an emphasis on the shape effect of the solid fillers on the lithium ion transference number and thus the electrochemical performance of the resulting SPE

    更新日期:2019-12-25
  • Using Peanut Shell to Construct Porous MnO/C Composite Material with Highly Improved Lithium‐storage Performance
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-23
    Dan Zhan; Tao Wen; Yuqi Li; Yuqing Zhu; Ke Liu; Ping Cui; Zhiyong Jia; Huajun Liu; Kelin Lei; Zuoan Xiao

    Rational utilization of biomass waste into the new clean energy such as lithium ion battery is conducive to alleviating energy crisis and environmental protection. Herein, using peanut shell as the carbon source, MnO/C composite material was successfully prepared through an eco‐environmental and facile approach based on hydrothermal treatment and pyrolysis. The resultant MnO/C composite material demonstrated hierarchical porous structure and MnO particles with irregular morphology were embedded in the pores. When used in lithium‐ion battery, the material exhibited much better lithium‐storage property than that for pristine MnO and peanut shell‐derived carbon. In 0.0‐3.0 V, the composite material can supply an initial specific capacity of 1169.5 mA h g‐1, with a capacity retention ratio of 84.9% after 200 electrochemical cycles. Even at 2400 mA g‐1, the material can still offer a discharge capacity of 532.3 mA h g‐1, manifesting the outstanding rate performance. The above enhanced lithium‐storage property of the composite material is contributed to the support of the porous carbon matrix derived from peanut shell, which is not only conducive to improve conductivity but also capable of buffering the volume expansion/shrinkage caused by lithiation/delithiation during charge/discharge process.

    更新日期:2019-12-25
  • 更新日期:2019-12-23
  • An Ordered Mesoporous Carbon Nanofiber Array for the Sensitive Electrochemical Detection of Malachite Green
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-23
    Beibei Yang; Duan Bin; Tongtong Tian; Yun Liu; Baohong Liu
    更新日期:2019-12-23
  • Boosting microbial fuel cells performance by the combination of an external supercapacitor: an electrochemical study
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-22
    Federico Poli; Jacopo Seri; Carlo Santoro; Francesca Soavi

    Microbial fuel cell (MFC) technology despite being a promising technology suffers of low power generation that hinders in most of the cases its application as power sources. In fact, usually, MFCs are coupled with supercapacitors or batteries and these storage units accumulate the energy harvested by MFCs and deliver it on demand. In this work, the electrodes of a MFC are used as electrodes of an internal supercapacitor and discharges and self‐recharges are performed and investigated. Discharges between 1.5 mA and 4 mA were presented producing a maximum power of 1.59 mW. Discharges between 1 mA and 100 mA and recharges are systematically studied for three commercial supercapacitors (SCs) having different capacitance of 1 F, 3 F and 6 F respectively. MFC was also parallel connected with external SCs connected in parallel and discharged galvanostatically. SC was self‐recharged by the MFC without any additional external power sources. At lower current pulses, MFC contributed to the overall capacitance probably due to its faradaic component. At higher current pulses, the use of SCs enable to get the energy harvested by MFCs at power levels that could not be achieved with MFC alone. This study demonstrates that by a proper connection and operation mode of MFC and SC it is possible to improve and maximize the performance of each single unit. Understanding the MFC‐ SC combination is important for identifying the right practical application for which the combination is suitable.

    更新日期:2019-12-23
  • The Effect of Dual‐Salt Concentrated Electrolytes on the Electrochemical Performance of Silicon Nanoparticles
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-20
    Zenghua Chang; Xiang Li; Fengling Yun; Zechao Shao; Zhaohui Wu; Jiantao Wang; Shigang Lu

    As a promising anode material, silicon has attracted extensive attention. The instability of electrode/electrolyte interphase due to the inherent volume variation upon (de)lithiation is one of the major factors limiting the commercialization of silicon anode materials. Here we report a concentrated electrolyte with dual‐salt of Lithium bis(fluorosulfonyl)imide (LiFSI) and Lithium Difluoro (Oxalate) Borate (LiDFOB) to enhance the control of the species constituting the solid electrolyte interphase (SEI) on the surface of silicon material. The silicon nanoparticle (SiNP) electrode with the dual‐salt concentrated electrolyte of LiFSI0.7LiDFOB0.3‐(PC)4 delivers a relatively high average coulombic efficiency of 97.68% and a remarkably improved cycling performance with an initial capacity of ca. 3300 mAh g‐1 and a capacity retention of ca. 2000 mAh g‐1 after 100 cycles. It is found that the polarity of B‐F bond of LiDFOB decreases when the molar ratio of LiDFOB to LiFSI is greater than 0.3:0.7. Therefore, the reduction of LiDFOB through a ring‐opening reaction coupled with a ring‐opening reaction of PC becomes dominant. The SEI layer rich in the corresponding products Li(BF2O)n polymer could suppress the rupture of the Si particles and excessive growth of the SEI layer, thus could further mitigate the decrease of coulombic efficiency.

    更新日期:2019-12-21
  • A solid‐state hybrid supercapacitor assembled by heterostructured Co‐Ni battery‐like cathode and SC‐typed highly disordered carbon nanosheets
    ChemElectroChem (IF 3.975) Pub Date : 2019-12-20
    Zhan Li; Kongjun Ma; Hongyu Mi; Chenchen Ji; Zhiwei Li; Fengjiao Guo; Shixue He; Conghui Wang; Mengjiao Xu; Huan Pang

    Hybrid at either the mechanism or the device level can lead to a hybridization effect to the kinetics and electrochemical characteristic of a SC. Herein, a heterostructured NiCo2S4/CoxNi1‐x(OH)2 battery‐like cathode material was designed, from which the obtained sample accomplished the combination of excellent electronic and ionic conductivity so as to realize an enhanced faradaic redox storage process. Besides, a SC‐typed highly capacitive anode material of a N and S co‐doped porous carbon nanosheet (ACNS) was also fabricated, which exhibits great advantages in its enlarged specific surface areas, easy to introduce pseudocapacitive reactions and physical structures. These features would directly lead to the significant improvements in the EDLC‐typed electrochemical properties of the carbon anode. The combination of EDLC‐typed carbon anode with the redox reaction‐typed cathode in a full cell device would potentially lead to the charge storage process simultaneous integrates the electrophysical and electrochemical process. Due to these reasons, the obtained solid‐state hybrid SC delivers a wide voltage window of 1.6 V, a high specific capacity of 121.3 C g‐1, an enhanced energy/power density of 26.1 Wh kg‐1/11 kW kg‐1. The as‐assembled device can keep high and stable capacity retention of 89.1% for over 10,000 cycles. The developed hybird assembled strategy and the electrode combination may provide design guidelines for designing other high‐energy hybrid SC.

    更新日期:2019-12-21
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