Understanding the synthesis of inorganic solid-state electrolytes for Li ion batteries: Features and progress

Inorganic solid electrolytes (ISEs) have recently attracted tremendous research interest because of their excellent thermal stability and nonflammability. The synthesis methods influence ISEs in the aspect of phase structure, ratio of amorphous phases, strain, defects, grain size, grain boundary resistance, impurities, and morphology, thus critically determining their performance in batteries. However, the relation between the synthesis of ISEs and their performance is complicated and there is no widely applicable synthesis method for all ISEs. To guide those who are deciding on synthesis methods for ISEs, a broad survey is reported in this review. The mechanisms of these synthesis methods are illustrated. Their advantages and disadvantages are sorted. Novel methods up to date, which can intrigue new ideas are also introduced based on our insights into the ISEs.