Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (1): 143-149.doi: 10.19799/j.cnki.2095-4239.2020.0238

• Energy Storage Materials and Devices • Previous Articles     Next Articles

Effects of concentrated electrolytes on the electrode /electrolyte interface

Jingjing ZHANG(), Xiaoling CUI(), Dongni ZHAO, Li YANG, Jie WANG   

  1. College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050, Gansu, China
  • Received:2020-07-08 Revised:2020-08-03 Online:2021-01-05 Published:2021-01-08

Abstract:

As an important way to improve the energy density of lithium-ion batteries is to utilize concentrated electrolytes. Concentrated electrolytes are able to regulate the structure, chemical composition, and stability of the interface between electrolytes and electrodes in lithium-ion batteries because of their differences from low-concentration electrolytes. The features of concentrated electrolytes have a potential broad application in improving the comprehensive electrochemical performance of batteries including the safety, cycle stability, and discharge rate. The special advantages of concentrated electrolytes compared with low-concentration electrolytes in recent years were reviewed in this article. It was found that concentrated electrolytes had the ability to widen the electrochemical stability window of electrolytes, inhibit the corrosion of aluminum current collectors, prevent graphite stripping, and other markers of improved compatibility between electrolytes and electrodes. We focused on the mechanism analysis of concentrated electrolytes on the electrode/electrolyte interface with increased lithium salt concentration, including the occupation of lithium salt anions in the electric double layer and solvated structures formed from lithium salt anions, solvents, and lithium ions. The structural and chemical composition of the interface film was also analyzed, along with its ability to form a thin and dense interface film. The application of new characterization techniques to the special solvation structure generated in the film formation process of concentrated electrolytes at the electrode/electrolyte interface were introduced, and the future development and research direction of concentrated electrolytes were also discussed.

Key words: Li-ion battery, concentrated electrolytes, interface, solvation, compatibility

CLC Number: