锂电池混合盐体系的界面作用及研究进展

为进一步提升锂电池的能量密度,解决常规单盐电解质存在的热稳定性差、电导率低、锂枝晶等问题,发展新型混合盐电解质成为锂电池电解质重要的研究方向之一,锂盐的混合可以改变溶液离子电导率、锂离子溶解度、黏度等性质,通过对电极/电解质界面以及电极材料表界面的影响来改善电池电化学性能.本文收集整理国内外最新研究文献,综述了锂电池混合盐电解质的研究进展,包括锂离子电池、锂金属电池、锂硫电池、全固态电池等不同的研究方向.总结了常见单盐的优势以及不足,从正负极以及集流体等不同角度分析了混合电解质在不同电池内部对于界面的影响,分析了不同文献关于其界面作用的相关机理解释,整理了混合电解质在不同电池体系中的应用.最后,对混合盐电解质以及界面作用的现有问题进行了论述,对新型混合电解质以及界面作用的表征发展方向及应用前景进行了展望,混盐体系研究多数仅限于性能改进,其作用机制还需要深入研究,现有解释通常从单盐出发,而不同锂盐实现协同作用的机制是未来的重要研究方向.

Interface reaction and research progress of blended-salts in lithium batteries

To improve the energy density of lithium (Li) batteries and solve the problems of conventional single-salt electrolytes such as poor thermal stability, low conductivity, and Li dendrites, developing new blended-salts electrolytes has become an important research direction of Li battery electrolytes. Blended-salts can change the ion conductivity, Li ion solubility, viscosity, and other properties of the solution, and can improve the electrochemical performance of the battery by affecting the interface of electrode and electrolyte as well as the surface and interface of electrode materials. This paper collects the latest research literature at home and abroad, and reviews the research progress of blended-salts electrolytes for Li batteries, including different research directions such as Li ion batteries, Li metal batteries, Li sulfur batteries, and solid state batteries. The advantages and disadvantages of commonly used single-salts are summarized, the effects and mechanism explanations of hybrid electrolytes on different surface interfaces of batteries are elaborated, and the applications of blended-salts in different battery systems are analyzed. At last, the existing problems of blended-salts electrolytes and interface reactions are discussed, and the development direction and application of characterization of novel blended-salts and interface reactions are given. The current research studies of blended-salts are mostly limited to performance improvement and its mechanism needs to be further investigated. The existing explanation usually unfolds from single-salts, and the mechanism of synergistic effect of blended-salts is an important research direction in the future.