Unveiling the effect of structural water on Zn-ion storage of polyoxovanadate for high-rate and long-life aqueous zinc ion battery
Unveiling the effect of structural water on Zn-ion storage of polyoxovanadate for high-rate and long-life aqueous zinc ion battery
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DOI：
10.1016/j.cej.2023.142221
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发表时间：
2023-03
影响因子：
15.1
通讯作者：
Huanze He;Fujun Pan;Xuesong Liang;Q. Hu;Shude Liu;Jisong Hu;Seong Chan Jun;Dunmin Lin;Y. Yamauchi;Yu-jia Huo
中科院分区：
文献类型：
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作者：
Huanze He;Fujun Pan;Xuesong Liang;Q. Hu;Shude Liu;Jisong Hu;Seong Chan Jun;Dunmin Lin;Y. Yamauchi;Yu-jia Huo
由于其低成本、高理论能量密度和高安全性，水溶液锌离子电池（ZIB）具有用于电网规模储能的前景;然而，具有稳定内部结构和足够的Zn 2+扩散通道的先进阴极材料的合理设计仍然是一个挑战。迄今为止，大多数研究都集中在电极材料的结构水，以改善其电化学动力学，而没有考虑其可能的负面影响。本文以Na 6 [V10 O28]·nH 2 O为研究对象，制备了具有可控结构水的多钒酸盐（NVO-n，n = 18，2.6和0），并将其用作锌离子的存储阴极，为研究水分子对电化学性能的影响提供了模型对象。结果表明，适量的结构水通过屏蔽Zn 2+离子的有效电荷而改善离子传输，同时减少对Zn 2+离子迁移的阻碍，从而实现快速Zn 2+存储。此外，NVO-2.6具有多电子氧化还原能力和高结构稳定性，这确保了在高工作电压（0.98 V）下高度可逆的Zn 2+嵌入/脱嵌和循环时小的体积应变。因此，经过优化的NVO-2.6在0.1 A g− 1下具有228.5 mAh g− 1的高比容量，并具有长期循环性能，在10 A g−1下循环3000次后容量保持率为89.7%。该研究为钒氧酸盐阴极的设计提供了新的方向。
Aqueous zinc-ion batteries (ZIBs) are promising for grid-scale energy storage because of their low cost, high theoretical energy density, and high safety; however, the rational design of advanced cathode materials with stable internal structures and sufficient Zn2+diffusion channels remains a challenge. To date, most studies have focused on the structural water of electrode materials to improve their electrochemical kinetics without considering its possible negative effects. Herein, we develop the polyoxovanadates of Na6[V10O28]·nH2O with controllable structural water (denoted as NVO-n, n = 18, 2.6 and 0) as cathodes for Zn2+storage, which provide model objects to study the effects of water molecules on electrochemical properties. Results reveal that an appropriate amount of structural water improves ion transport by shielding the effective charge of Zn2+ions while reducing the hindrance to the migration of Zn2+ions, enabling fast Zn2+storage. Moreover, the NVO-2.6 possesses multi-electron redox ability and high structural stability, which ensures the highly reversible Zn2+intercalation/de-intercalation at a high working voltage (0.98 V) and small volumetric strain upon cycling. Consequently, the optimized NVO-2.6 delivers a high specific capacity of 228.5 mAh g−1at 0.1 A g−1and a long-term cyclability with 89.7% capacity retention after 3000 cycles at 10 A g−1. This study paves a new direction for the design of polyoxovanadate-based cathodes toward high-performance ZIBs.