Kim SaeWon, Shan Xiaoqiang, Abeykoon Milinda, Kwon Gihan, Olds Daniel, Teng Xiaowei
Department of Chemical Engineering, University of New Hampshire, Durham, New Hampshire 03824, United States.
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States.
ACS Appl Mater Interfaces. 2021 Jun 9;13(22):25993-26000. doi: 10.1021/acsami.1c04279. Epub 2021 May 21.
Aqueous Zn-ion batteries (AZIBs) are promising alternatives to lithium-ion batteries in stationary storage. However, limited storage capacity and cyclic life impede their large-scale implementation. We report reversible electrochemical insertion of multi-ions into sodium vanadate (NaVO) cathode materials for AZIBs, achieving a maximum storage capacity of 450 mAh g at 0.05 A g and a capacity retention of 82% after 500 cycles at 0.4 A g. In addition to Zn and H insertion, in situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) collectively provide explicit evidence on vanadyl ions (VO) conversion-intercalation at the NaVO cathode, showing the deintercalation of VO from NaVO and the consequent conversion of VO into VO on charging, and vice versa on discharging. Our study is the first to report on the cation conversion-intercalation mechanism in AZIBs. This reversible multi-ion storage mechanism provides a design principle for developing high-capacity aqueous electrode materials by engaging both the intercalation and conversion of charge carriers.
水系锌离子电池（AZIBs）在固定储能领域有望成为锂离子电池的替代方案。然而，有限的存储容量和循环寿命阻碍了它们的大规模应用。我们报道了在AZIBs的钒酸钠（NaVO）阴极材料中多离子的可逆电化学插入，在0.05 A g时实现了450 mAh g的最大存储容量，在0.4 A g下500次循环后容量保持率为82%。除了锌和氢的插入外，原位X射线衍射（XRD）和X射线吸收光谱（XAS）共同提供了钒酰离子（VO）在NaVO阴极处发生转化插层的明确证据，显示出充电时VO从NaVO中脱嵌并随之转化为VO，放电时则相反。我们的研究首次报道了AZIBs中的阳离子转化插层机制。这种可逆的多离子存储机制为通过电荷载流子的插层和转化来开发高容量水系电极材料提供了设计原则。
