Abstract:

Compared with the traditional liquid lithium-ion battery, a solid-state lithium battery (SSLB) uses a solid electrolyte instead of an organic electrolyte to greatly improve safety and energy density, which can effectively reduce safety risks of electric vehicles and relieve users' anxiety. A solid electrolyte is one of the core elements of SSLB and serves as the electronic insulator and ionic conductor. However, several problems, such as the low ionic conductivity, large interface impedance, and poor interface stability, exist with the use of this electrolyte. Based on the discussion of relevant literatures, the ionic conduction mechanism, and the research progress of sulfide solid electrolyte, oxide solid electrolyte, polymer solid electrolyte, and composite solid-electrolyte SSLB, the main problems and solutions of these four solid electrolytes were mainly reviewed and discussed in this work. For the improvement of ionic conductivity, the methods for adjusting the composition of solid electrolytes were introduced. As for the improvement of the interface, this work introduced the idea of interface design and manufacturing process. The comprehensive analysis showed that the performance of solid electrolytes can be effectively improved through doping and coating modification, exploration of the advanced interface research and diagnosis technology, and guidance of interface design with an excellent lithium-ion transport capacity, and innovation and optimization of the process. Finally, the industrialization processes of solid-state lithium batteries in domestic and foreign key enterprises were listed, and the future application prospect of solid-state lithium batteries was analyzed and prospected.

Key words: oxide solid electrolyte, sulfide solid electrolyte, polymer solid electrolyte, composite solid electrolyte, industrialization progress