Prospects of LLZO type solid electrolyte: From material design to battery application

• Challenges and opportunities in garnet SSBs towards early commercialization is illustrated. • The mechanical, thermodynamic, and air stability of garnet SSEs are delighted to ensure high performance all-solid-state SSBs. • Garnet SSEs based all-solid-state SSBs have better safety compared to liquid lithium batteries. • The hybriding of garnet with other flexible materials can make flexible SSBs available. Solid-state batteries (SSBs) with high energy density and excellent safety are expected to be the next-generation energy storage devices to replace traditional lithium-ion batteries (LIBs). Garnet solid-state electrolytes (SSEs) have attracted extensive attention due to their many advantages, such as high ionic conductivity and stability. This review systematically summarizes the challenges and solutions faced by garnet SSBs. First, the structural evolution of garnet SSEs is introduced, the advanced nature of Li 7 La 3 Zr 2 O 12 (LLZO) is pointed out, and the kinetic mechanism and stability of LLZO and the corresponding improvement schemes are discussed. Second, a variety of solid-state interface engineering that breaks the bottleneck of traditional methods is introduced. Third, the batteries before and after modification are summarized and compared with LIBs to demonstrate the high energy and safety of SSBs. Finally, two new perspectives on cost and sustainability provide corresponding improvements. We investigate the entire life cycle of garnet SSBs from production to disposal, providing guidance for the realization of inexpensive and environmentally friendly SSBs with high ionic conductivity, stability, and energy density.