A review on the failure and regulation of solid electrolyte interphase in lithium batteries

Solid electrolyte interphase (SEI) has been widely recognized as the most important and the least understood component in lithium batteries. Considering the intrinsic instability in both chemical and mechanical, the failure of SEI is inevitable and strongly associated with the performance decay of practical working batteries. In this Review, the failure mechanisms and the corresponding regulation strategies of SEI are focused. Firstly, the fundamental properties of SEI, including the formation principles, and the typical composition and structures are briefly introduced. Moreover, the common SEI failure modes involving thermal failure, chemical failure, and mechanical failure are classified and discussed, respectively. Beyond that, the regulation strategies of SEI with respect to different failure modes are further concluded. Finally, the future endeavor in further disclosing the mysteries of SEI is prospected.