Robust VS4@rGO nanocomposite as a high-capacity and long-life cathode material for aqueous zinc-ion batteries
Robust VS4@rGO nanocomposite as a high-capacity and long-life cathode material for aqueous zinc-ion batteries
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坚固的 VS4@rGO 纳米复合材料作为水性锌离子电池的高容量和长寿命正极材料
DOI：
10.1039/d1nr02158c
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发表时间：
2021-06-30
期刊：
影响因子：
6.7
通讯作者：
Shan, Chongxin
中科院分区：
文献类型：
--
作者：
Chen, Kaijian;Li, Xing;Shan, Chongxin
虽然基于钒(V)的硫化物作为水基锌离子电池(ZIB)的正极已被研究，但其性能的改善和锌离子(Zn2+)的内在储存机理的揭示仍然具有挑战性。本文设计了具有优化结构的VS4@RGO复合材料，并将其应用于水基ZIBs正极材料，表现出超高的比容量(0.5A g(-1)时的450mA h g(-1))和高倍率容量(10A g(-1)时的313.8 mA h g(-1))。此外，VS4@rGO正极具有长寿命循环稳定性，在10Ag(-1)下循环3500次后容量保持率接近82%。通过原位X射线衍射/拉曼光谱和透射电子显微镜分析，进一步探讨了VS4在脱电过程中的结构演变、氧化还原和退化机理。结果表明，VS4的主要储能机制来自于VS4明渠中的插层/脱插层反应。值得注意的是，充电过程中VS4向中心点2H(2)O(ZVO)转变为不可逆的相变，而在长时间循环过程中进一步从ZVO向ZnV3O8转变，这可能是导致VS4@rGO容量下降的主要原因。我们的研究通过形貌设计进一步提高了VS4在水基ZIBs中的电化学性能，并对VS4中锌离子存储的储能和性能退化机理提供了新的见解，从而为V基硫化物在储能系统中的大规模应用提供了新的思路。
Although vanadium (V)-based sulfides have been investigated as cathodes for aqueous zinc-ion batteries (ZIBs), the performance improvement and the intrinsic zinc-ion (Zn2+) storage mechanism revelation is still challenging. Here, VS4@rGO composite with optimized morphology is designed and exhibits ultrahigh specific capacity (450 mA h g(-1) at 0.5 A g(-1)) and high-rate capability (313.8 mA h g(-1) at 10 A g(-1)) when applied as cathode material for aqueous ZIBs. Furthermore, the VS4@rGO cathode presents long-life cycling stability with capacity retention of similar to 82% after 3500 cycles at 10 A g(-1). The structural evolution, redox, and degradation mechanisms of VS4 during (dis)charge processes are further probed by in situ XRD/Raman techniques and TEM analysis. Our results indicate that the main energy storage mechanism is derived from the intercalation/deintercalation reactions in the open channels of VS4. Notably, an irreversible phase transition of VS4 into Zn-3(OH)(2)V2O7 center dot 2H(2)O (ZVO) during the charging process and the further transition from ZVO to ZnV3O8 during long-term cycles are also observed, which might be the main reason leading to the capacity degradation of VS4@rGO. Our study further improves the electrochemical performance of VS4 in aqueous ZIBs through morphology design and provides new insights into the energy storage and performance degradation mechanisms of Zn2+ storage in VS4, and thus may endow the large-scale application of V-based sulfides for energy storage systems.