Phase-Field Modeling of Solid Electrolyte Interphase (SEI) Evolution: Considering Cracking and Dissolution during Battery Cycling

Abstract

The Lithium-ion battery (LIB) degrades over time, which compromises its electrochemical performance and mechanical integrity, eventually battery safety. The evolution of solid electrolyte interphase (SEI) layer is one of the main reasons for the above degradation. The performance and longevity of LIB highly depend on the stability of the SEI. Unfortunately, the SEI layer is not electrochemically and mechanically stable due to the dissolution and cracking of the SEI during battery cycling. In this paper, a phase field model is developed to provide insight into the interaction of cracking and dissolution of the SEI layer. SEI layer experiences stress concentration and de/intercalation, which lead to the cracking of layer; meanwhile, the SEI species may have further reactions with the electrolyte which may lead to dissolution. The cracking of the SEI layer can result in more surfaces to react with electrolyte and further dissolution.