Li Zhi, Wu Buke, Yan Mengyu, He Liang, Xu Lin, Zhang Guobin, Xiong Tengfei, Luo Wen, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10420-10427. doi: 10.1021/acsami.9b21579. Epub 2020 Feb 20.
A rechargeable aqueous zinc-ion battery (ZIB) is one of the attractive candidates for large-scale energy storage. Its further application relies on the exploitation of a high-capacity cathode and the understanding of an intrinsic energy storage mechanism. Herein, we report a novel layered KVO cathode material for the ZIB, adopting a strategy of charging first to extract part of K-ions from vanadate in initial few cycles, which creates more electrochemically active sites and lowers charge-transfer resistance of the ZIB system. As a result, a considerable specific capacity of 302.8 mA h g at 0.1 A g, as well as a remarkable cycling stability (92.3% capacity retention at 4 A g for 2000 cycles) and good rate capability, are achieved. Besides, the energy storage mechanism was studied by in situ X-ray diffraction, in situ Raman spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma mass spectroscopy. An irreversible K-ion deintercalation in the first charge process is proved. It is believed that this novel cathode material for the rechargeable aqueous ZIB and the optimizing strategy will shed light on developing next-generation large-scale energy storage devices.
可充电水系锌离子电池（ZIB）是大规模储能领域颇具吸引力的候选者之一。其进一步应用依赖于高容量阴极的开发以及对内在储能机制的理解。在此，我们报道了一种用于ZIB的新型层状KVO阴极材料，采用在最初几个循环中先充电以从钒酸盐中提取部分K离子的策略，这创造了更多的电化学活性位点并降低了ZIB系统的电荷转移电阻。结果，在0.1 A g下实现了302.8 mA h g的可观比容量，以及出色的循环稳定性（在4 A g下循环2000次容量保持率为92.3%）和良好的倍率性能。此外，通过原位X射线衍射、原位拉曼光谱、X射线光电子能谱和电感耦合等离子体质谱研究了储能机制。证明了在首次充电过程中存在不可逆的K离子脱嵌。相信这种用于可充电水系ZIB的新型阴极材料及其优化策略将为开发下一代大规模储能装置提供启示。
