先进液态金属电池熔盐电解质的设计  

Design of Advanced Performance Halide Molten Salt Electrolytes for Liquid Metal Battery

作　　者：王心桥 张健[1] 苏彤 赵兴 郭永权[1] WANG Xinqiao;ZHANG Jian;SU Tong;ZHAO Xing;GUO Yongquan(School of Energy Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206

出　　处：《材料导报》2022年第1期110-116,共7页Materials Reports

基　　金：国家重点研发计划(2018YFB0905601)。

摘　　要：本工作系统研究了液态金属电池多元熔融盐电解质体系的优化,利用X-射线衍射和扫描电镜系统研究四组元卤族熔盐电解质的相结构和微观组织,利用Rietveld结构精修方法测定各相的晶体结构;利用差示扫描量热法测定四组元熔盐电解质的熔化温度;建立离子钢球模型计算熔盐密度和负极金属在熔融电解质中的溶解度,发现实验值与理论值相符。通过成分和性能优化获得低熔点、低溶解度的熔盐电解质体系:0.232LiCl-0.08LiBr-0.488LiI-0.2KI和0.203LiCl-0.07LiBr-0.427LiI-0.3KI。其熔化温度约为260℃,明显低于目前已开发的电解质,有望拓宽液态金属电池工作温区,减少能耗。经计算,当工作温度为400℃时,负极金属Li、Na在优化的两种熔盐体系中的溶解度分别约为0.2%和0.9%,有利于提高电池的效率;熔盐电解质的密度为2.67~2.68 g/cm^(3),介于液态阴极和阳极的密度之间,可稳定阴极/电解质/阳极层结构;离子电导率大于1.0 S/cm,符合液态金属电池对熔融盐电解质性能的要求。The study is focused on the improvement of multiple alkali metal halide molten salt electrolytes for liquid metal battery.The X-ray diffraction and scanning electron microscopy are used to check the various phases,phase structures and microstructures in the quaternary system of alkali metal halide molten salt electrolytes in this study.The crystal structures of molten salts are determined with a Rietveld method.The melting points of molten salts are measured by differential scanning calorimetry.The density of molten salt and the solubility of metal cation in molten electrolyte are theoretically investigated with a rigid model,the calculated values fit the experimental ones well.The two advanced performance molten salts with compositions of 0.232LiCl-0.08LiBr-0.488LiI-0.2KI and 0.203LiCl-0.07LiBr-0.427LiI-0.3KI are obtained with properties of low melting point and low solubility by composition and performance optimization.The melting temperature is around 260℃,which is beneficial for reducing the running temperature and energy consumption.At the operating temperature of 400℃,the metal solubility in two molten electrolyte is about 0.2%for Li and 0.9%for Na,respectively,which is helpful for improving the efficiency of the batteries.The density of molten salt electrolyte is 2.67—2.68 g/cm^(3),which is between the density of liquid cathode and anode.It can stabilize the structure of cathode/electrolyte/anode three layers and separate the cathode and anode.The ionic conductivity is predicted to be more than 1.0 S/cm.The conductivity of molten salt electrolyte meets the requirement of liquid metal battery.

关 键 词：液态金属电池电解质 熔融盐 碱金属卤化物 密度 溶解度 

分 类 号：TB32[一般工业技术—材料科学与工程]