Emerging Superionic\nSulfide and Halide Glass–Ceramic\nSolid Electrolytes: Recent Progress and Future Perspectives

Solid-state batteries (SSBs) are attracting attention\nas safe,\nhigh-energy and high-power-density electrochemical energy-storage\nsystems. However, they are not yet capable of outperforming advanced\nlithium-ion batteries using liquid electrolytes. A critical obstacle\nrelates to the development of cost-effective, inorganic solid electrolytes\n(SEs), combining superionic conductivity with high (electro)chemical\nstability and mechanical softness. Realizing intrinsically soft inorganic\nSEs is particularly challenging. Glass–ceramic SEs offer several\nadvantages but typically exhibit low ionic conductivities. Given the\nrecent developments of sulfide- and halide-based glass–ceramic\nmaterials, the overall objective of designing superionic (inorganic)\nSEs, entailing polymer- or clay-like softness, seems feasible. These\nSEs benefit from lower processing temperatures and versatile chemistries\nthat allow for further enhancements. This Review provides a comprehensive\noverview of recent developments in the field of lithium glass–ceramic\nSEs and maps out factors governing conductivity and mechanical behavior.\nFinally, opportunities, challenges, and design principles for next-generation\nSEs are discussed.