Ultrafast gas–solid synthesis of Li4SiO4 sorbent from spent lithium-ion batteries via high-temperature shock

Harvesting functional materials from spent lithium-ion batteries (LIBs) presents an opportunity to enhance the economic value of products derived via recycling while mitigating the environmental footprint associated with battery waste management. This study reports an innovative high-temperature shock (HTS)-driven gas–solid (G–S) synthesis strategy that leverages the lithium (Li) from waste LiCoO₂ (LCO) powder to efficiently prepare Li₄SiO₄ sorbent. An initial HTS step at approximately 1000 °C induces rapid, in situ vaporization of Li₂O from the LCO matrix, which subsequently reacts with SiO₂ powder, forming a precursor material while simultaneously reducing the LCO residue to metallic cobalt (purity >96 %). The Li₄SiO₄ sorbent was successfully synthesized following a transient thermal lithiation treatment at 1200 °C for 20 s. The HTS-induced Li volatilization and G–S synthesis mechanisms were elucidated via advanced characterization and theoretical calculations. The resultant Li₄SiO₄ sorbent demonstrated commendable CO₂ adsorption performance, maintaining a stable adsorption capacity of 0.193 g/g after undergoing 20 consecutive adsorption–desorption cycles under a 15 vol% CO₂ atmosphere. This study introduces a novel short-process, highly efficient, and sustainable strategy for the upcycling of spent LIBs and illuminates new pathways for the rapid synthesis of functional materials.