Hu Bingbing, Li Dongshan, Li Meixin, Jiang Jiayu, Zhao Yingyang, Du Tianlun, Zhou Zideng, Pu Hong, Ma Guangqiang, Li Zhi
China-Spain Collaborative Research Center for Advanced Materials, College of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074, China.
Sichuan Vanadium Titanium Materials Engineering Technology Research Center, Panzhihua University, Panzhihua 617000, Sichuan, China.
Inorg Chem. 2025 Mar 31;64(12):6042-6052. doi: 10.1021/acs.inorgchem.4c05245. Epub 2025 Mar 17.
Prussian blue analogs (PBAs) have attracted significant attention for use in aqueous zinc-ion batteries (AZIBs) because of their open framework, tunability, and ease of preparation. However, PBAs are still faced with low specific capacity or poor cycling performance as cathode materials for AZIBs, which is attributed to the insufficient number of active sites and structural instability due to water molecules. In this study, vanadium with multivalent properties has been introduced to form a dual active site with Fe, providing multiple electron transfers and possessing a higher specific capacity. Meanwhile, a coprecipitation method is used to form a β-cyclodextrin (β-CD) surface layer with an excluded-volume effect and rich hydroxyl side groups on the surface of vanadium hexacyanoferrate (VOHCF). The surface layer effectively prevents the direct interaction of VOHCF with active water molecules in the electrolyte while also regulating the desolvation structure of Zn, enhancing the long-cycle stability of electrode materials. The prepared β-cyclodextrin-vanadium hexacyanoferrate (β-CD-VOHCF) achieves a high reversible capacity (204.1 mAh·g at 0.2 A·g), and the capacity retention ratio improves by 65% compared with VOHCF after 3200 cycles at 5 A·g. This study offers new ideas to inhibit vanadium dissolution and establish a foundation for the development of VOHCF.
普鲁士蓝类似物（PBAs）因其开放框架、可调性和易于制备，在水系锌离子电池（AZIBs）中的应用备受关注。然而，作为AZIBs的阴极材料，PBAs仍面临比容量低或循环性能差的问题，这归因于活性位点数量不足以及水分子导致的结构不稳定。在本研究中，引入了具有多价性质的钒与铁形成双活性位点，提供多个电子转移并具有更高的比容量。同时，采用共沉淀法在六氰合铁酸钒（VOHCF）表面形成具有体积排阻效应和丰富羟基侧基的β-环糊精（β-CD）表面层。该表面层有效防止VOHCF与电解质中的活性水分子直接相互作用，同时还调节锌的去溶剂化结构，增强电极材料的长循环稳定性。制备的β-环糊精-六氰合铁酸钒（β-CD-VOHCF）实现了高可逆容量（在0.2 A·g时为204.1 mAh·g），在5 A·g下循环3200次后，与VOHCF相比容量保持率提高了65%。本研究为抑制钒溶解提供了新思路，并为VOHCF的发展奠定了基础。
