摘要
Cathode electrolyte interphase(CEI)has a significant impact on the performance of rechargeable batteries and is gaining increasing attention.Understanding the fundamental and detailed CEI formation mechanism is of critical importance for battery chemistry.Herein,a diverse of characterization tools are utilized to comprehensively analyze the composition of the CEI layer as well as its formation mechanism by LiCoO_(2)(LCO)cathode.We reveal that CEI is mainly composed of the reduction products of electrolyte and it only parasitizes the degraded LCO surface which has transformed into a disordered spinel structure due to oxygen loss and lithium depletion.Based on the energy diagram and the chemical potential analysis,the CEI formation process has been well explained,and the proposed CEI formation mechanism is further experimentally validated.This work highlights that the CEI formation process is nearly identical to that of the anode-electrolyte-interphase,both of which are generated due to the electrolyte directly in contact with the low chemical potential electrode material.This work can deepen and refresh our understanding of CEI.
基金
Natural Science Foundation of Beijing,China,Grant/Award Number:2212003
National Natural Science Foundation of China for Youth Science Fund,Grant/Award Number:12204025
National Natural Science Fund for Innovative Research Groups,Grant/Award Number:51621003
Beijing municipal high level innovative team building program,Grant/Award Number:IDHT20190503
The U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences,Division of Materials Sciences and Engineering,Synthesis and Processing Science Program,Grant/Award Number:10122。