Self-assembled nanostructures of PDI-bolaamphiphiles as anode materials for advanced rechargeable Na-ion batteries
Graphical abstract
Controllable morphologies including nanofibers, nanospheres, and nanoneedles are synthesized from PDI-bolaamphiphiles by altering the aminoacid side chain. The NF electrode (Nanofiber-LP-Phe) electrode possesses superior specific capacity, rate capability and cycle performance. The influence of morphology on electrochemical performance of the battery was systematically investigated.
Introduction
Sodium-ion batteries (NIBs) have been considered as smart alternative for lithium-ion batteries (LIBs), owing to their natural abundance, widespread, economical, eco-friendly and similar electrochemical characteristics [1]. The conventional inorganic anode materials for NIBs, typically encounter limited Na+ ion insertion/ extraction, due to the larger radius of Na+ ion (1.02 Å), resulting in poor capacity and inadequate cycling stability [2,3]. Currently, organic electrode materials (OEMs) have been pursued as promising alternative anode materials for NIBs, because of their structural flexibility, potential multi-electron reactions, and tunable voltage range. However, their applicability is still constrained by poor electronic conductivity, low reversible capacity, and undesired dissolution in organic electrolytes [4]. In order to address these issues, recently, nanostructured strategies has been significantly improved sodium transport kinetic performance, owing to their robust nanoarchitecture, porous morphology with a high surface area (offers more active sites and eases the penetration of electrolytes) [5], [6], [7]. Hence, the combination of OEM and nanostructure engineering should be an effective approach to improve the electrochemical performance of anode materials in NIBs. However, still more research is required to properly utilize nanostructured organic anodes for practical applications, and improving the cycling stability at higher current density, and eliminating the dissolution issue permanently are the still key challenges.
Anode material is a vital component and had a direct impact on battery performance. For the proper development of NIBs choosing an appropriate anode material is the greatest challenge. Attributes such as vast resources, structural flexibility (facilitates the excellent mobility of large sized Na-ions), electronic properties, light weight, recyclability, easy functionalization, and eco-friendliness have put organic electrode materials as potential alternative anode materials [2,8,9]. So far, carboxylates [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], quinones [20], anhydrides, ketone, and imides [2,8,9] have been investigated to some extent as anode materials in NIBs. These organic molecules held together by non-covalent interactions such as van der Waals forces, hydrogen bonding, or ion binding, which results in a large interlayer spacing and creates low energy barriers for the reversible accommodation of the large Na ions [21]. Among them carboxylates have been extensively utilized as anode materials, includes monosodium terephthalate (C8H5NaO4) [10], disodium terephthalate (Na2C8H4O4) [11], and so on [12], [13], [14]. However, they delivered less capacity and poor cycling performance due to their dissolution in organic electrolytes. Although, after introduction of hetero atom (N, S, O) in to the aromatic backbone of carboxylates has resulted in improved specific capacity, but their dissolution has shown a detrimental impact on both kinetics and cycling stability [15], [16], [17], [18], [19]. Polymerization of small organic molecules is a better method, to overcome the current dissolution issues in electrolytes. For instance, Zhao, Qinglan, et al. synthesized interconnected nanosheets with a microflower-like morphology from pyromellitic dianhydride (PMDA)-based polyimides [C16H6O4N2]n and their corresponding anodes were displayed a discharge capacity of 125 mAh g−1 at a current density of 25 mA g−1 over 100 cycles [22]. Similarly, Li, Zhongtao and co-workers synthesized covalent polyimides from naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) cross-linked melamine and used as anode material for NIBs. The obtained electrodes retained a capacity of 88.8 mAh g−1 at a current density of 5 A g−1 over 1000 cycles [23]. According to the findings of the preceding investigations, the polymerization method improved the stability of the material but delivered significantly less specific capacity due to the increase in molecular weight.
To circumvent it, the extension of π-conjugated structures is a feasible strategy, as it can able to stabilize the charge/discharge states while facilitating ion diffusion [9,21]. 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA), an organic semiconductor and dye is considered to be a better anode material for NIBs, owing to its strong electron affinity, high electronic conductivity, fast reaction kinetics for metal-ions storage, multiple Na+ binding sites per molecular unit, better electrolyte stability and good thermal stability [24], [25], [26], [27], [28]. So far, many researchers have utilized PTCDA as cathode material [[24], [25], [26],28], unfortunately, there has been a very limited progress in PTCDA and its derivatives as anode material for NIBs [27,29,30]. Although, they are still in the early stage of development and it is also necessary to explore novel PTCDA derivatives to address the current scientific problems.
Herein, we report the design and synthesis of biomimetic engineered PDI bolaamphiphiles with aromatic (phenylalanine-Phe), heterocyclic/ heteroaromatic (tryptophan-Trp) and aliphatic (glutamic acid-Glu) amino acid substituents (Scheme 1a), which can self-assemble into nanofibers, nanospheres, and nanoneedles, respectively, and were further stabilized by hydrogen bonding and π-π interactions. Subsequently, the obtained nanostructures served as the anode materials for Na-ion battery. The presence of hydrophilic free carboxylic acid groups in the PDI bolaamphiphile structure can helps to reduce their solubility against organic electrolyte and allows them to serve as electron-rich sites for cation (Na+) storage. We systematically investigated the influence of the structure and morphology of PDI bolaamphiphiles on the electrochemical performance of the NIBs. Among the three electrodes, the NF electrode has been delivered the highest specific capacity, improved rate capability, and demonstrated stable cycle performance at higher current density (1 A g−1) over 1000 charge–discharge cycles. The excellent electrochemical performance of the NF can be attributed to its nanofiber morphology with a stable structure, high electrical conductivity, and proper insertion/extraction mechanism. Moreover, the synthesis of nanostructures from PDI bolaamphiphiles is an easy, sustainable, and economical approach; possibly fulfill the needs for large-scale battery applications.
Section snippets
Materials
3,4,9,10-Perylene tetracarboxylic acid dianhydride (98%), L-Phenylalanine (99%), D-Phenylalanine (99%), L-Tryptophan (99%), D-Tryptophan (99%), L-Glutamic Acid (99%), D-Glutamic Acid (99%), and imidazole were purchased from Adamas chemicals, Shanghai, China. The remaining common solvents and general chemicals like tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), methanol and hydrochloric acid were obtained from Tansoole and Adamas chemicals, Shanghai, China, and used without any further
Circular dichroism (CD) spectroscopy
In order to access the influence of enantiomeric amino acids on the chiroptical properties of achiral PDI chromophore, we carried out CD measurements in THF and DMSO solvents by varying the water ratio. Notably, when the water-to-THF/DMSO fraction was increased from 0% to 99%, both the absorption and CD spectra showed a dynamic conversion. Fig. 1a depicts the CD spectra of LP-Phe and DP-Phe in THF with different water fractions (c = 1 × 10−5 M). In pure THF, LP-Phe showed a small negative CD
Conclusion
In conclusion, we have successfully synthesized various nanostructures from PDI-bolaamphiphiles by altering the amino acid substituents using a simple solvent exchange self-assembly approach and used them as anode electrode materials for NIBs. This research offers a practical and efficient approach for tuning the electrochemical properties of NIBs using the various nanostructures. Our findings demonstrated that the improved cycling performance of NF electrode is attributed to its highly stable
CRediT authorship contribution statement
Sravan Baddi: Conceptualization, Data curation, Methodology, Investigation, Writing – original draft. Usman Ghani: Methodology. Juexin Huang: Methodology. Qinglei Liu: Supervision. Chuan-Liang Feng: Funding acquisition, Supervision, Writing – review & editing.
Declaration of Competing Interest
The authors declare no potential conflicts of interest with respect to the authorship and/or publication of this article.
Acknowledgments
This work was supported by the National Nature Science Foundation of China (51833006), the Innovation Program of Shanghai Municipal Education Commission (201701070002E00061), the Science and Technology Commission of Shanghai Municipality (20S31904600, 19ZR1425400), SJTU Trans-med Awards Research (WF540162603), Ministry of Science and Technology of the People's Republic of China, Foreign Youth Talent Program, QN2021134001.
References (54)
- et al.
Nanostructured electrode materials for advanced sodium-ion batteries
Matter
(2019) - et al.
Nanostructured strategies towards boosting organic lithium-ion batteries
J. Energy Chem.
(2021) - et al.
Nanostructured conversion-type anode materials for advanced lithium-ion batteries
Chem
(2018) - et al.
A carboxylate group-based organic anode for sustainable and stable sodium ion batteries
J. Power Sources
(2020) - et al.
Bipyridine carboxylic acid as a high-performance anode material for lithium-and sodium-ion batteries
Electrochim. Acta
(2022) - et al.
Pyromellitic dianhydride-based polyimide anodes for sodium-ion batteries
Electrochim. Acta
(2018) - et al.
Synthesis of three dimensional extended conjugated polyimide and application as sodium-ion battery anode
J. Chem. Eng.
(2016) - et al.
Ultra-stable, ultra-long-lifespan and ultra-high-rate Na-ion batteries using small-molecule organic cathodes
Energy Storage Mater.
(2021) - et al.
Activating aromatic rings as Na-ion storage sites to achieve high capacity
Chem
(2018) - et al.
Characterization of novel perylene diimides containing aromatic amino acid side chains
Spectrochim. Acta A Mol. Biomol. Spectrosc.
(2016)