The Growth Mechanism of the Solid Electrolyte Interphase on Graphite Electrodes during Storage

INTRODUCTION A typical commercial lithium-ion cell with graphite electrodes always undergoes a formation process at its manufacture site, during which a protective solid electrolyte interphase (SEI) film forms on the graphite electrodes. After the formation treatment, the lithium-ion cell usually has to undergo a long-term storage before their application. Thus, a clear understanding of the longterm storage characteristics of the SEI film is quite important since it has been generally accepted now that the SEI film plays a critical role on determining the electrochemical performance of the lithium-ion cells [1]. The thickness of SEI during storage usually increases. To our knowledge, the mechanism of SEI growth during storage is not so clear so far and especially the quantitative description of SEI thickness growth against time or temperature was seldom reported. In this work, we will report the growth mechanism of SEI on graphite electrodes during storage in combination with references and our data.