Chen Wei, Wu Jiahao, Fu Kai, Deng Zhaohui, Chen Xingbao, Cai Hongwei, Wu Xinfei, Xing Boyu, Luo Wen, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, Hubei, 430070, P. R. China.
Department of Physics, School of Science, Wuhan University of Technology, Wuhan, 430070, P. R. China.
Small Methods. 2024 Jun;8(6):e2300617. doi: 10.1002/smtd.202300617. Epub 2023 Jul 9.
Manganese hexacyanoferrate (MnHCF) is one of the most promising cathode materials for aqueous battery because of its non-toxicity, high energy density, and low cost. But the phase transition from MnHCF to Zinc hexacyanoferrate (ZnHCF) and the larger Stokes radius of Zn cause rapid capacity decay and poor rate performance in aqueous Zn battery. Hence, to overcome this challenge, a solvation structure of propylene carbonate (PC)-trifluoromethanesulfonate (Otf)-HO is designed and constructed. A K/Zn hybrid battery is prepared using MnHCF as cathode, zinc metal as anode, KOTf/Zn(OTf) as the electrolyte, and PC as the co-solvent. It is revealed that the addition of PC inhabits the phase transition from MnHCF to ZnHCF, broaden the electrochemical stability window, and inhibits the dendrite growth of zinc metal. Hence, the MnHCF/Zn hybrid co-solvent battery exhibits a reversible capacity of 118 mAh g and high cycling performance, with a capacity retention of 65.6% after 1000 cycles with condition of 1 A g. This work highlights the significance of rationally designing the solvation structure of the electrolyte and promotes the development of high-energy-density of aqueous hybrid ion batteries.
六氰合铁酸锰（MnHCF）因其无毒、高能量密度和低成本，是水系电池中最具潜力的正极材料之一。但在水系锌电池中，MnHCF向六氰合铁酸锌（ZnHCF）的相变以及Zn较大的斯托克斯半径会导致容量快速衰减和倍率性能不佳。因此，为克服这一挑战，设计并构建了碳酸丙烯酯（PC）-三氟甲磺酸根（Otf）-HO的溶剂化结构。使用MnHCF作为正极、锌金属作为负极、KOTf/Zn(OTf)作为电解质以及PC作为共溶剂制备了K/Zn混合电池。结果表明，PC的加入抑制了MnHCF向ZnHCF的相变，拓宽了电化学稳定窗口，并抑制了锌金属枝晶的生长。因此，MnHCF/Zn混合共溶剂电池表现出118 mAh g的可逆容量和高循环性能，在1 A g的条件下1000次循环后容量保持率为65.6%。这项工作突出了合理设计电解质溶剂化结构的重要性，并推动了高能量密度水系混合离子电池的发展。
