Research progress on space charge layer effect in lithium-ion solid-state battery

The development of lithium-ion solid electrolyte provides new ideas for solving the safety problems of secondary lithium-ion batteries(LIB) and, at the same time, the improvement of energy density. However, the consequent solid-solid interfacial problems have become a typical bottleneck to the performance. It has been considered that the space charge layer(SCL) formed at the interface to balance the sharp electrochemical inherent difference of properties is one of the most important factors that affect the ion transportation along and across the interface. Its existence may hinder ion transportation and increase the interfacial impedance but may also help to provide a new percolation path for lithium ion and so to enhance the ion migration. However the mechanism of SPL formation and its regulation on ion transport is not very clear, so it has raised a lot of attention and interest from LIB researchers. The purpose of this article is to try to gain some knowledge of SCL and, at the same time to browse through the related research in recent years. Hopefully, it may help those interested in solid electrolyte development for all-solidstate lithium-ion batteries(ASSB) in the future.