无机双盐水系钠离子电解质的设计及低温性能研究  

Design of inorganic double salt aqueous sodium ion electrolyte and research on its low temperature performance

作　　者：李奔 杨程 刘家和 刘宇[1] LI Ben;YANG Cheng;LIU Jiahe;LIU Yu(Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海硅酸盐研究所,上海200050 [2]中国科学院大学,北京100049

出　　处：《电源技术》2023年第12期1526-1532,共7页Chinese Journal of Power Sources

基　　金：国家自然科学基金(52202121);内蒙古科技计划(2021ZD0033);中国三峡集团(WWKY-2021-0027)。

摘　　要：水系钠离子电池由于其环境友好、安全性高等优势成为储能技术的理想选择之一,然而水系电解质相对较高的凝固点限制了储能器件在低温环境下的应用。设计了一种无机双盐水系钠离子电解质,通过引入与钠离子、水分子的结合能不同的CH_(3)COO^(-)和Cl^(-)两种阴离子,调控水中的氢键网络结构和电解质盐电离过程,降低强氢键比例,形成了更多的[Na(H_(2)O)_(6)]^(+)。基于该设计,无机双盐水系钠离子电解质的凝固点低至-30.1℃,而且在-20℃下仍然保持较高的离子电导率(23.24 mS/cm)。使用该电解质组装的Na_(2)CoFe(CN)_(6)||PTCDI全电池在-20℃下能够表现出52.6 mAh/g的比容量(0.1 A/g),且在0.2 A/g的电流密度下可以实现500次稳定循环。Aqueous sodium ion batteries have become one of the ideal choices for energy storage technology due to their environmental friendliness and high safety.However,the relatively high freezing point of aqueous electrolytes limits the application of energy storage devices in low temperature environments.In this work,an inorganic double salt aqueous sodium ion electrolyte was designed.By introducing CH3COO-and Cl-anions with different binding energies from sodium ions and water molecules,the hydrogen bond network structure in water and the ionization process of electrolyte salt were regulated,the proportion of strong hydrogen bonds was reduced,and more[Na(H_(2)O)_(6)]^(+)was formed.Based on this design,the freezing point of the inorganic double salt aqueous sodium ion electrolyte is reduced to-30.1℃,and the ionic conductivity remains high at-20℃(23.24 mS/cm).Na_(2)CoFe(CN)_(6)||PTCDI full cell assembled with this electrolyte exhibits a specific capacity of 52.6 mAh/g(0.1 A/g)at-20℃,and can achieve 500 cycles at a current density of 0.2 A/g.

关 键 词：水系钠离子电解质 氢键网络 凝固点 离子电导率 

分 类 号：TM912[电气工程—电力电子与电力传动]