超低浓度电解液助力K0.486V2O5高性能质子存储

Ultralow-concentration electrolyte boosting K0.486V2O5 for high-performance proton storage

高浓度电解液被认为是一种很有前景的拓宽电解液电化学稳定窗口和提高水系电池电化学性能的方法.但是高浓度电解液也存在高成本、高粘度、低电导率等棘手问题.因为特殊的Grotthuss机制,质子电池能够在低浓度电解液中获得足够的动力学性能.基于此,我们采用罕见的超低浓度硫酸电解液(0.01 mol L^(-1))助力K~+预嵌的VO(KVO,KVO)电化学稳定性.在50 mA g^(-1)的低电流密度下,KVO电极具有129 mA h g^(-1)的比容量;在1 A g^(-1)的电流密度下,循环20,000圈的容量保持率为78%.超低浓度电解液策略为开拓耐用的、低成本的水系能源存储系统提供了一种新的路径.

High-concentration electrolytes are considered a promising tool for widening stable electrochemical windows and enhancing the electrochemical performance of aqueous batteries.However,their high cost,high viscosity,and low conductivity remain thorny issues.Because of the special Grotthuss mechanism of protons in water,proton batteries can use a low-concentration electrolyte to obtain sufficient kinetic performance.Herein,we present an unusual,ultralowconcentration sulfuric acid(0.01 mol L)electrolyte to boost the electrochemical stability of K-ion pre-intercalated VO(KVO,KVO).The KVO electrode exhibits a high reversible capacity of approximately 129 mA h g^(-1)at a low current density of 50 mA g^(-1)and impressive capacity retention of78%over 20,000 cycles at 1 A g^(-1).Ultralow-concentration electrolyte chemistry will open a novel route to exploit durable and low-cost aqueous energy storage systems.