3.9 V电化学稳定窗口的乙酸盐电解液用于低成本高性能的水系钠离子电池  

Acetate Solutions with 3.9 V Electrochemical Stability Window as an Electrolyte for Low-Cost and High-Performance Aqueous Sodium-Ion Batteries

作　　者：兰道云 屈小峰 唐宇婷 刘丽英[1] 刘军[1] Dao-Yun Lan;Xiao-Feng Qu;Yu-Ting Tang;Li-Ying Liu;Jun Liu(Guangdong University of Technology,Guangzhou 510006,Guangdong,China)

机构地区：[1]广东工业大学,广东广州510006

出　　处：《电化学》2022年第1期55-64,共10页Journal of Electrochemistry

基　　金：国家自然科学基金面上项目(编号21673051);广东省科技厅国际合作项目(编号2019A050510043)和广东省科技厅产学研重大专项(编号2017B010119003)资助。

摘　　要：水系钠离子电池因其低成本和高安全性有望在大规模储能领域得到广泛应用,但稀水溶液的电化学稳定窗口窄(1.23 V),限制了钠离子电池的能量密度。"water-in-salt"盐包水策略可有效扩宽水的电化学稳定窗口。本文中通过使用高浓度的乙酸铵(CH_(3)COONH_(4),25 mol·L^(-1))与乙酸钠(CH;COONa,5 mol·L^(-1)),将水的电化学稳定窗口扩宽至3.9 V。该高浓度水溶液与MnO_(2)/CNTs正极和NaTi_(2)(PO_(4))_(3)/C负极组装的全电池平均工作电压为1.3 V,容量可以达到74.1 mAh·g^(-1)。Low-cost and high-safety aqueous sodium-ion batteries have received widespread attention in the field of large-scale energy storage,but the narrow electrochemical stability window (1.23 V) of water limits the energy density of aqueous sodium-ion batteries.The“water-in-salt”strategy which uses the interaction between cations and water molecules in the solution can inhibit water decomposition and broaden the electrochemical stability window of water.In this work,two types of low-cost salts,namely,ammonium acetate (NH;CH;COOH) and sodium acetate (NaCH;COOH),were used to configure a mixed aqueous electrolyte for aqueous sodium-ion batteries.The solution consisted of 25 mol·L^(-1)NH;CH;COOH and 5 mol·L^(-1)NaCH;COOH,used as an aqueous electrolyte,exhibited a wide electrochemical stability window of 3.9 V and high ionic conductivity of 28.2 m S·cm;.The composite of layered manganese dioxide and multi-wall carbon nanotubes (MnO_(2)/CNTs) was used as a positive electrode material,while the carbon-coated NaTi_(2)(PO_(4))_(3)with NASICON structure was used as a negative electrode material.Both of these electrode materials had excellent electrochemical performances in the aqueous electrolyte.A full cell achieved an average working voltage of about 1.3V and a discharge capacity of 74.1 mAh·g^(-1)at a current density of 0.1 A·g^(-1).This aqueous sodium-ion battery displayed excellent cycling stability with negligible capacity losses (0.062%per cycle) for 500 cycles.The safe and environmentally friendly aqueous acetate electrolyte,with a wide electrochemical stability window,showed the potential to be matched with positive materials having higher potential and negative materials having lower potential for further improving the voltage of aqueous sodium-ion batteries and promoting the development of aqueous batteries for large-scale energy storage technology.

关 键 词：钠离子电池 水系电解液 乙酸铵 盐包水 

分 类 号：TM912[电气工程—电力电子与电力传动]