In-Situ Investigation of the Cathode Electrolyte Interphase Formation, Kinetics, and Composition

Solid electrolyte interphase studies are the next avenue for improving the performance of rechargeable lithium-ion batteries. The cathode electrolyte interphase (CEI) plays a critical role in stabilizing lithium composite cathodes which are known to suffer parasitic side reactions that lead to rapid capacity fade, cathode degradation, and thermal runaway. However, the CEI is under-reported compared to the solid electrolyte interphase on the anode because of its complex surface chemistry, nanoscale structure, and the high potential that next-generation cathodes undergo during cycling. There is ambiguity in the relationship between cathode properties and the formation, kinetics, and performance of CEI, which, if resolved, could lead to a further understanding of the conditions that produce a stable CEI and provide guidance for engineering more effective CEI. In this work, lithium manganese oxides were used as a case study to investigate the CEI’s in-situ behavior in terms of formation, kinetics, and composition.