Li Chuan, Li Qing, Wu Zhuoxi, Wang Yiqiao, Zhang Rong, Cui Huilin, Hou Yue, Liu Jiahua, Huang Zhaodong, Zhi Chunyi
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, 999077, China.
Hong Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Shatin, NT, HKSAR, 999077, China.
Adv Mater. 2024 Apr;36(17):e2304878. doi: 10.1002/adma.202304878. Epub 2023 Aug 30.
Metal hexacyanoferrates are recognized as superior cathode materials for zinc and zinc hybrid batteries, particularly the Prussian blue analog (PBA). However, PBA development is hindered by several limitations, including small capacities (<70 mAh g) and short lifespans (<1000 cycles). These limitations generally arise due to incomplete activation of redox sites and structure collapse during intercalation/deintercalation of metal ions in PBAs. According to this study, the adoption of a hydroxyl-rich (OH-rich) hydrogel electrolyte with extended electrochemical stability windows (ESWs) can effectively activate the redox site of low-spin Fe of the KFeMn[Fe(CN)]·zHO (KFeMnHCF) cathode while tuning its structure. Additionally, the strong adhesion of the hydrogel electrolyte inhibits KFeMnHCF particles from falling off the cathode and dissolving. The easy desolvation of metal ions in the developed OH-rich hydrogel electrolytes can lead to a fast and reversible intercalation/deintercalation of metal ions in the PBA cathode. As a result, the Zn||KFeMnHCF hybrid batteries achieve the unprecedented characteristics of 14 500 cycles, a 1.7 V discharge plateau, and a 100 mAh g discharge capacity. The results of this study provide a new understanding of the development of zinc hybrid batteries with PBA cathode materials and present a promising new electrolyte material for this application.
金属六氰合铁酸盐被认为是锌及锌混合电池的优质阴极材料，尤其是普鲁士蓝类似物（PBA）。然而，PBA的发展受到若干限制，包括容量小（<70 mAh g）和寿命短（<1000次循环）。这些限制通常是由于PBA中金属离子嵌入/脱嵌过程中氧化还原位点的不完全活化和结构坍塌所致。根据这项研究，采用具有扩展电化学稳定窗口（ESW）的富羟基（OH富）水凝胶电解质可以有效活化KFeMn[Fe(CN)]·zHO（KFeMnHCF）阴极低自旋Fe的氧化还原位点，同时调整其结构。此外，水凝胶电解质的强粘附性可抑制KFeMnHCF颗粒从阴极脱落和溶解。在开发的富OH水凝胶电解质中金属离子易于去溶剂化，可导致PBA阴极中金属离子快速且可逆的嵌入/脱嵌。结果，Zn||KFeMnHCF混合电池实现了14500次循环、1.7 V放电平台和100 mAh g放电容量的前所未有的特性。这项研究的结果为使用PBA阴极材料的锌混合电池的发展提供了新的认识，并为该应用提供了一种有前景的新型电解质材料。
