Liu Lu, He Zixi, Wu Binghan, Song Hongjia, Zhong Xiangli, Wang Jinbin, Zou Daifeng, Cheng Juanjuan
School of Materials Science and Engineering, Key Laboratory of Low-dimensional Materials and Application Technology, Xiangtan University, Xiangtan 411105, P. R. China.
School of Materials Science and Engineering, Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Department of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, P. R. China.
Phys Chem Chem Phys. 2024 Sep 18;26(36):23811-23822. doi: 10.1039/d4cp02704c.
Aqueous zinc-ion batteries are considered potential large-scale energy storage systems due to their low cost, environmentally friendly nature, and high safety. However, the development of high energy density cathode materials and uncertain reaction mechanisms remains a major challenge. In this work, the reaction mechanism, discharge voltage and diffusion properties of layered CrO as a cathode material for aqueous zinc-ion batteries were studied using first-principles calculations, and the effect of pre-intercalated structural water on the electrochemical performance of CrO electrodes is also discussed. The results show that CrO exhibits high average discharge voltages (2.65 V for H insertion (pH = 7) and 1.97 V for Zn insertion) and medium theoretical capacities (319 mA h g (H and Zn)). The H intercalation voltage strongly depends on the pH value of the electrolyte. The H/Zn co-insertion mechanism occurs at low hydrogen concentrations ((H) ≤ 0.125), where the initial insertion of H reduces the total amount of subsequent Zn insertion. For the substrate containing structured water (CrO·HO, ≥ 0.5), the average voltage of Zn insertion is significantly increased, while the average voltage of H slightly decreases. In addition, the pre-intercalated water strategy significantly improved the diffusion properties of H and Zn. This study shows that layered CrO·HO is a promising cathode material for aqueous zinc-ion batteries, and also provides theoretical guidance for the development of high-performance cathode materials for aqueous zinc-ion batteries.
水系锌离子电池因其低成本、环境友好和高安全性而被认为是潜在的大规模储能系统。然而，高能量密度阴极材料的开发和不确定的反应机制仍然是一个重大挑战。在这项工作中，使用第一性原理计算研究了层状CrO作为水系锌离子电池阴极材料的反应机制、放电电压和扩散特性，并讨论了预嵌入结构水对CrO电极电化学性能的影响。结果表明，CrO表现出较高的平均放电电压（H插入时为2.65 V（pH = 7），Zn插入时为1.97 V）和中等的理论容量（319 mA h g（H和Zn））。H嵌入电压强烈依赖于电解质的pH值。H/Zn共嵌入机制发生在低氢浓度（（H）≤0.125）下，其中H的初始嵌入会减少随后Zn嵌入的总量。对于含有结构水的底物（CrO·H₂O，≥0.5），Zn插入的平均电压显著增加，而H的平均电压略有下降。此外，预嵌入水策略显著改善了H和Zn的扩散特性。这项研究表明，层状CrO·H₂O是一种有前景的水系锌离子电池阴极材料，也为水系锌离子电池高性能阴极材料的开发提供了理论指导。
