(Invited) Stability and Evolution of Solid Electrolyte Interphase on Silicon Anodes

Abstract

Solid electrolyte interphase (SEI), which forms at the interface between the electrolyte and the electrode, can passivate the surface of graphite anodes and finally facilitate the intercalation of lithium ions into graphite electrodes. However, the concept of only using SEI protects the electrode surface from the reductive electrolyte may be not applicable for silicon (Si) anodes. Different from the intercalation chemistry in graphite anodes, Si anodes experience alloying/dealloying reactions during electrochemical process, leading to phase transformation, morphology and volumetric changes. It generates great complexity in understanding the formation and the structural/composition evolution of the SEI layer during electrochemical process. Considering the high theoretical capacity Si anodes can offer, the investigation of SEI behavior on Si anodes is critical for developing next-generation anode materials. This presentation, which is based on recent results from advanced electrochemical and spectroscopy characterization, systematically elaborates the chemical and physical properties of SEI toward mitigation strategies for stabilizing SEI on Si anodes.