Closed-Loop Recycling and Re-Synthesis of Lithium-Rich Ceramic Electrolytes for Next-Generation All-Solid-State Batteries: A Conceptual Framework

The surge in demand for lithium-ion batteries (LIBs) and the advent of all-solid-state batteries (ASSBs) have intensified concerns over resource sustainability and end-of-life waste management. Conventional recycling approaches primarily focus on cathode materials, often neglecting lithium recovery and the recycling potential of solid electrolytes. In this study, a closed-loop recycling and re-synthesis strategy for lithium-rich ceramic electrolytes has been proposed, with a focus on garnet-type Li7La3Zr2O12 (LLZO), a promising candidate for ASSB applications. The proposed methodology integrates hydrometallurgical recovery of lithium and critical metals from spent LIBs, followed by the direct re-synthesis of LLZO through controlled solid-state reaction pathways. Emphasis is placed on maintaining chemical purity, controlling microstructure, and enhancing ionic conductivity through doping and sintering optimization. Preliminary studies demonstrate that recycled LLZO precursors can achieve comparable ionic conductivity and electrochemical stability to those derived from virgin materials, validating the functional recycling approach. A techno-economic and life cycle assessment underscores the potential environmental and cost benefits of adopting closed-loop recycling for ceramic electrolytes in ASSB manufacturing. This work paves the way for sustainable, circular battery production by integrating material recovery with advanced solid electrolyte engineering.