Sandwich-like honeycomb Co2SiO4/rGO/honeycomb Co2SiO4 structures with enhanced electrochemical properties for high-performance hybrid supercapacitor
Graphical abstract
Introduction
Energy is closely bound up our lives and the inquisition about new energy sources and various energy storage technologies has been ever-lasting. As a type of energy storage devices, supercapacitors (SCs) recently stand out among the crowded competition of batteries and conventional physical capacitors, and researchers pay a great of interest in SCs owing to their outstanding characteristics including high-power density, wide temperature range, long cycling life, free maintenance, green and environmentally friendly [[1], [2], [3], [4], [5], [6]]. Generally, SCs can be divided into two kinds on account of the energy storage mechanisms: electric double layer capacitors (EDLCs) and pseudo-capacitors (PCs) [7]. As is well known, EDLCs are originated from the surface of electrodes forming the double layers, and PCs store charge through redox reactions [7]. As for high-performance SCs, the energy density (E) is a crucial factor because the high energy density decides the long operation of the devices in the practical application. The E is calculated by the equation E = 1/2CV2, where C represents the specific capacitance and V means the working voltage. Obviously, the high energy density is decided by the specific capacitance and voltage range. Thus, it is essential to develop and design electrode materials with special structure showing high electrochemical properties [[8], [9], [10], [11], [12]].
Owing to the low costs, nontoxic, easier to structure adjustment and stability, the transition metal silicates (TMSs) with high theoretical capacity have been received great attention in the field of energy storage devices [[13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28]]. For examples, Wang et al. [22] demonstrated that mesoporous metal (Mn, Co, Ni) silicates with hollow spheres exhibited good electrochemical properties as the electrode materials for SCs. Typically, the mention of silicate-based electrode is followed by cobalt silicate (Co2SiO4) based electrode owing to its high theoretical capacity and stability [29]. Recent studies demonstrate that cobalt silicate-based materials are considered as the potential electrode materials for SCs [[29], [30], [31], [32], [33], [34]]. For example, Cheng et al. synthesized coupled Co2SiO4 nanobelt-on-nanobelt with rGO using Co2SiO4 nanobelt as the templates and this composite exhibited improved supercapacitive properties [32]. All the previous works illustrated that the study on the synthesis and electrochemical properties of Co2SiO4 has achieved great progress. However, it still exists some insufficiency due to the experimental capacitance being lower than its theoretical value caused by the poor conductivity of Co2SiO4 [15]. In order to gain the high performance of Co2SiO4 for SCs, a scientific and reasonable strategy for the improvement of the conductivity Co2SiO4 by designing novel structures is extremely important among many constraints [29,32]. At present, the mainstreams to improve the conductivity of Co2SiO4 with novel structures are as follows: (1) Preparation of bimetallic silicate by virtue of the difference of electrical conductivity between bimetallic silicate [33]; (2) Carbon/silicon in biomass was used as the skeleton to grow Co2SiO4 for high conductivity [[35], [36], [37]]; (3) The conductive material (CNTs, GO, carbon paper and carbon cloth, etc.) is introduced to improve the conductivity of the Co2SiO4 composite electrode [32,34]. Especially, it should be pointed out that the third method that mixing conductive material with TMSs to prepare composite electrode is inefficient [38]. The properties of the two-phase hybrid can't provide a rapid path for electrons transmission, and the conductivity problem is seemingly solvable, which is extremely negligible [[39], [40], [41]]. The concept of the growth of Co2SiO4 on the conductive material (e.g.: rGO) may be a good tool to improve the electrochemical performance of Co2SiO4 [42]. This concept “Two for one” means that we put the two-phase (Co2SiO4 and rGO) into one-phase (Co2SiO4/rGO integrated composite) [43]. Based on the above assumption, we try to construct the Co2SiO4/rGO/Co2SiO4 sandwich-like structures using the sandwich-like GO/SiO2 as the template to improve the electrochemical properties of Co2SiO4. This structure may enhance the electrochemical performance of Co2SiO4 on the basis of the following two aspects: (1) The rGO in the middle of the sandwich-like structures can boost the conductivity of the electrode materials. That's to say, once the electrons flow to the rGO, they can quickly flow to outside Co2SiO4 [44]. (2) The integrated structure can be conducive to the electron/mass transfer kinetics [14].
As expected, herein, we successfully developed a strategy for the preparation of the sandwich-like honeycomb Co2SiO4/rGO/honeycomb Co2SiO4 structures (denoted as s-rGO/Co2SiO4) using the sandwich-like GO/SiO2 as the template by a moderate hydrothermal method. Co2SiO4 nanosheets on the surface of rGO are interconnected to form the 3D honeycomb-like structures. This novel material exhibited improved electrochemical properties compare to Co2SiO4 and the results are corresponding with our original aim. This work provides an effective method for the synthesis of metal silicates/rGO/metal silicates sandwich-like structures with enhanced electrochemical performances for energy storage applications and conversions.
Section snippets
Synthesis
The raw materials and the synthesis of GO and rGO are represented in Supplementary data. The sandwich-like honeycomb Co2SiO4/rGO/honeycomb Co2SiO4 structures (denoted as s-rGO/Co2SiO4) were prepared using sandwich-like GO/SiO2 as the template by a hydrothermal method (Fig. 1), which mainly contains three steps. Firstly, the GO sheets were synthesized by a modified Hummer's method (see in Supplementary data). Secondly, GO/SiO2 was prepared by a reformative StÖber technology [43]. In detail,
Structure and composition of s-rGO/Co2SiO4
Fig. 1 describes the formation process of s-rGO/Co2SiO4 as well as the mechanism procedure of GO/SiO2. As shown in Fig. 1, the formation process of s-rGO/Co2SiO4 mainly included two stages of the generation of GO/SiO2 template and the hydrothermal process of s-rGO/Co2SiO4. Firstly, the sandwich-like GO/SiO2 template (Figure S1) is prepared by a reformative StÖber technology [43], and the process is further decomposed into two stages [22]: (1) the in-situ hydrolysis process of Si(OC2H5)4 and (2)
Conclusion
In conclusion, s-rGO/Co2SiO4 was prepared using sandwich-like GO/SiO2 as the template by a hydrothermal method. The rGO is in the middle of this sandwich structure and Co2SiO4 nanosheets are interconnected to form the 3D honeycomb-like structures on the surface of rGO. This novel structure can improve the conductivity of s-rGO/Co2SiO4 to facilitate the electron transport and enhance the interaction between Co2SiO4 and rGO surface to promote the charge transfer. Thus, the s-rGO/Co2SiO4 exhibits
Author contributions
Yifu Zhang conceived the idea and directed the experiments. Xueying Dong and Yuting Yu fabricated all the samples. Xueying Dong and Yuting Yu performed the characterizations. Xueying Dong, Yuting Yu, Xuyang Jing, Hanmei Jiang, Tao Hu, Yifu Zhang, Changgong Meng and Chi Huang discussed the results and commented on the manuscript. Xueying Dong, Yuting Yu and Yifu Zhang analysed the data and drafted and revised the manuscript.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This work was partially supported by the National Natural Science Foundation of China (Grant No. 21771030) and Natural Science Foundation of Liaoning Province (2020-MS-113).
References (65)
- et al.
Mesoporous hollow carbon spheres boosted, integrated high performance aqueous Zn-Ion energy storage
Energy Storage Mater.
(2020) - et al.
Recent progress in metal-organic frameworks as active materials for supercapacitors
EnergyChem
(2020) - et al.
Metal–organic frameworks as a platform for clean energy applications
EnergyChem
(2020) - et al.
Metal-organic frameworks induced robust layered Co(OH)2 nanostructures for ultra-high stability hybrid supercapacitor electrodes in aqueous electrolyte
J. Power Sources
(2020) - et al.
Electrochemical performance of carbon-coated lithium manganese silicate for asymmetric hybrid supercapacitors
J. Power Sources
(2010) - et al.
Layered cobalt nickel silicate hollow spheres as a highly-stable supercapacitor material
Appl. Energy
(2015) - et al.
In-situ grown manganese silicate from biomass-derived heteroatom-doped porous carbon for supercapacitors with high performance
J. Colloid Interface Sci.
(2019) - et al.
Mixed-valent MnSiO3/C nanocomposite for high-performance asymmetric supercapacitor
J. Colloid Interface Sci.
(2019) - et al.
Designed mesoporous hollow sphere architecture metal (Mn, Co, Ni) silicate: a potential electrode material for flexible all solid-state asymmetric supercapacitor
Chem. Eng. J.
(2019) - et al.
Co2SiO4/SiO2/RGO nanosheets: boosting the lithium storage capability of tetravalent Si by using highly-dispersed Co element
Electrochim. Acta
(2018)
Electrochemical characteristics and impedance spectroscopy studies of nano-cobalt silicate hydroxide for supercapacitor
J. Power Sources
1D Co2.18Ni0.82Si2O5(OH)4 architectures assembled by ultrathin nanoflakes for high-performance flexible solid-state asymmetric supercapacitors
J. Power Sources
Coupled cobalt silicate nanobelt-on-nanobelt hierarchy structure with reduced graphene oxide for enhanced supercapacitive performance
J. Power Sources
Synthesis of amorphous cobalt silicate nanobelts@manganese silicate core–shell structures as enhanced electrode for high-performance hybrid supercapacitors
J. Colloid Interface Sci.
In-situ hydrothermal growth of Zn4Si2O7(OH)2·H2O anchored on 3D N, S-enriched carbon derived from plant biomass for flexible solid-state asymmetrical supercapacitors
Chem. Eng. J.
Alkali etching metal silicates derived from bamboo leaves with enhanced electrochemical properties for solid-state hybrid supercapacitors
Chem. Eng. J.
Cobalt-Nickel silicate hydroxide on amorphous carbon derived from bamboo leaves for hybrid supercapacitors
Chem. Eng. J.
Amorphous manganese silicate anchored on multiwalled carbon nanotubes with enhanced electrochemical properties for high performance supercapacitors
Colloid. Surface. Physicochem. Eng. Aspect.
V2O3/C nanocomposites with interface defects for enhanced intercalation pseudocapacitance
Electrochim. Acta
A flexible CNT@nickel silicate composite film for high-performance sodium storage
J. Energy Chem.
Copper silicate nanotubes anchored on reduced graphene oxide for long-life lithium-ion battery
Energy Storage Mater.
3D hierarchical porous V3O7·H2O nanobelts/CNT/reduced graphene oxide integrated composite with synergistic effect for supercapacitors with high capacitance and long cycling life
J. Colloid Interface Sci.
Amorphous cobalt silicate nanobelts@carbon composites as a stable anode material for lithium ion batteries
Chem. Sci.
Morphology and size controlled synthesis of Co-doped MIL-96 by different alkaline modulators for sensitively detecting alpha-fetoprotein
Chin. Chem. Lett.
Ammonium ion intercalated hydrated vanadium pentoxide for advanced aqueous rechargeable Zn-ion batteries
Mater. Today Energy
Fabrication and electrochemical properties of manganese dioxide coated on cobalt silicate nanobelts core-shell composites for hybrid supercapacitors
Colloid. Surface. Physicochem. Eng. Aspect.
Synthesis of Co2SiO4/Ni(OH)2 core–shell structure as the supercapacitor electrode material with enhanced electrochemical properties
Mater. Lett.
Design and mechanisms of asymmetric supercapacitors
Chem. Rev.
3D-Printed structure boosts the kinetics and intrinsic capacitance of pseudocapacitive graphene aerogels
Adv. Mater.
In situ grown 2D hydrated ammonium vanadate nanosheets on carbon cloth as a free-standing cathode for high-performance rechargeable Zn-ion batteries
J. Mater. Chem. A
Electrochemical capacitors: mechanism, materials, systems, characterization and applications
Chem. Soc. Rev.
A review of electrolyte materials and compositions for electrochemical supercapacitors
Chem. Soc. Rev.
Cited by (86)
Sandwich-like self-supported woodceramics electrodes modified with in-situ growth carbon nanotubes catalyzed by Co<sup>2+</sup>
2023, Journal of Alloys and CompoundsIn situ confined vertical growth of Co<inf>2.5</inf>Ni<inf>0.5</inf>Si<inf>2</inf>O<inf>5</inf>(OH)<inf>4</inf> nanoarrays on rGO for an efficient oxygen evolution reaction
2023, Nano Materials ScienceCitation Excerpt :From our studies, the poor conductivity of TMSs mainly restricts their performance in various ways in electrochemistry. Dong et al. demonstrated that rGO could greatly improve the specific capacitances of TMSs in alkaline electrolyte [40–43]. Thus, coupling TMSs with a conductive support is an effective strategy to accelerate ion and molecular diffusion, especially in electrocatalytic applications [44,45].
Phosphate-modified cobalt silicate hydroxide with improved oxygen evolution reaction
2023, Journal of Colloid and Interface ScienceHydrophobic dual metal silicate nanotubes for higher alcohol synthesis
2023, Applied Catalysis B: Environmental
- 1
These authors are equal to this work.