Comprehensive Investigation into Garnet Electrolytes Toward Application-Oriented Solid Lithium Batteries

To satisfy the ever-increasing demand for higher energy density, solid-state batteries (SSBs) have received significant attention due to their potential in providing energy densities greater than 400 Wh kg−1. And as a key material in SSBs, the garnet-type Li7La3Zr2O12 (LLZO) electrolyte is particularly promising because of its high ionic conductivity at room temperature and excellent chemical stability against Li metal. And although great progress has been achieved for garnet electrolytes, many critical issues remain in terms of the practical application of garnet-based SSBs with truly high energy densities. Based on this, this review will provide an overview of the current progress in solid garnet batteries in terms of electrolyte fabrication and interfacial engineering in prototype cells. In addition, various strategies used to meet application requirements are comprehensively reviewed, including not only strategies to enhance energy density, but also methods to enhance rate capability, extend cycle life, decrease cost and reduce thermal runaways. Furthermore, crucial challenges are presented and future research directions are proposed in the development of high-performance solid lithium batteries.