摘要
锂离子电池的使用领域明显受工作温度范围的限制。消费级电子设备要求的工作温度通常在-20~60℃,基本与常规锂离子电池极限工作温度一致;然而,为了适应地域和季节温度差异,电动汽车的动力电源通常需要长期在-30~70℃的温度范围内工作;宇航/军事装备需要更强的适应性,要求搭载的电池系统具备更宽的工作温度范围,特别是低温极限拓展至-50℃以下。目前锂离子电池显然难以在如此宽的温度范围内长时间、高性能地工作,因此宽温型锂离子电池成为研究开发的热点之一。宽温性能同时需要兼顾电池的高温和低温两方面的性能。文献表明,低温的主要问题是锂离子的扩散,为可逆过程,对原有电池组成和结构不造成显著破坏;高温的主要问题是电解液的分解和电解液与正极、负极间的表面化学钝化机制的丧失,为不可逆过程,导致电池循环充放电容量迅速衰减。碳酸酯基电解液的优化设计成为现阶段拓宽锂离子电池工作温度范围最可行、最经济的途径。宽温电解液的设计和研究涉及到电解液的溶剂化结构、电解液与负极以及电解液与正极的表面化学反应三方面的问题。其中,具有较宽的液态温度范围、较高的电化学稳定性和低温离子电导率是电解液液相的必要条件;而电解液|电极界面成分与结构是维持锂离子和电荷的交换、增强电解液与电极材料相容性的关键因素。液相改性主要通过采用新型电解质锂盐和使用具有较宽液态范围的共溶剂来实现,界面的改性主要通过向电解液中加入界面成膜添加剂和高温添加剂来实现。本文基于笔者课题组在电解液宽温化改性方面的工作,综述了近些年来宽温电解液的相关研究和探索方面的成果,介绍了最近报道的新型电解质锂盐、共溶剂和功能性添加剂的结构、性能及作用机理,并展望了宽温电解液研究的未来发展方向及研究方法。
Today the application of lithium-ion batteries(LIBs)is significantly limited by the operating temperature range.The operating temperature required for consumer electronic devices is usually-20—60℃,which is basically consistent with operating temperature of the available conventional lithium ion batteries.To adapt to regional and seasonal temperature differences of electric vehicles/hybrid electric vehicle,LIBs are idea-lly required to show high energy density similar to that at room temperature and maintain an excellent cycling performance from-30—70℃.To enhance the survival ability and adaptability,LIBs for certain military and space applications need much stricter requirement on wide temperature range.Especially,the low temperature limit should be lower than-50℃.Available LIBs are obviously difficult to work in such a wide temperature range for a long time,so LIBs with wide operating temperature have been attracted more attention in recent years.Wide operating properties should be simultaneously considered at both low and elevated temperature.The main problem at low temperature is the diffusion of lithium ion,which is a reversible process but does not cause significant damage to the composition and structure of original batte-ry.However,the main problems of elevated temperature are the decomposition of electrolyte and the chemical passivation loss of interfaces between electrolyte and positive/negative electrode.The irreversible process leads to the rapid decrease of discharge capacity and cycling perfor-mance.At present,electrolyte optimization is the most feasible and economical way to broaden the operating temperature range.The design and pro-perties studies of wide temperature electrolyte involve three aspects:the solvation of electrolyte,the surface chemical reaction between electrolyte and negative electrode,and the interface reaction on positive electrode.Liquid phase of electrolyte is basically required the wide range of liquid temperature,the high electrochemical stability and the ionic conductivity at low temperature.The interface composition and structure are the key factors to exchange the charges/lithium ions,and maintain the compatibility between electrolyte and electrode.Liquid phase modification is mainly realized through the use of new lithium salts and new wide temperature co-solvents,while interface modification is mainly carried out by the addition of interface film additives and high-temperature additives.In this paper,based on the studies of author and teammates,lots of research and exploration results on the electrolyte for wide temperature are reviewed.Novel lithium salts,co-solvents and functional additives reported in recent years are focused on their structures,properties and action mechanism.At the end,future prospect and research methods are given for lithium-ion battery electrolytes adapted wide operating temperature range.
作者
浦文婧
芦伟
谢凯
郑春满
PU Wenjing;LU Wei;XIE Kai;ZHENG Chunman(Institutes of Physical Science and Information Technology,Anhui University,Hefei 230601,China;Institute of Applied Physics,Army Academy of Artillery&Air Defense,Hefei 230031,China;Institute of College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第7期36-44,共9页
Materials Reports
基金
安徽省自然科学基金(1708085QB32)
国家自然科学基金(51576208,11505290)。
关键词
锂离子电池
电解液
宽使用温度
氟代酯
有机硅添加剂
lithium-ion battery
electrolyte
wide operating temperature
fluorinated ester
silicone additive
