Recovery of Battery-Grade Lithium Precursors via Electrochemical–Chemical Rejuvenation of Spent Primary Lithium Batteries

Abstract

Primary lithium (Li) metal batteries are widely used but are typically discarded after single-use operation, resulting in a dispersed and underutilized Li-containing waste stream. Here, we report an integrated electrochemical–chemical pathway for Li recovery from spent primary Li metal batteries. Residual Li is first reactivated through controlled electrochemical rejuvenation, inducing Li redeposition onto the anode-side casing. The regenerated Li is then selectively extracted and stabilized at the molecular level using a polycyclic aromatic hydrocarbon (PAH)–ether solution, followed by antisolvent-induced precipitation and moderate thermal conversion to lithium carbonate (Li₂CO₃). The effects of processing parameters, including drying atmosphere and calcination temperature, on phase evolution and Li content are systematically examined. The recovered Li₂CO₃ exhibits high crystallinity and Li purity, as further validated by the synthesis and electrochemical evaluation of lithium cobalt oxide (LiCoO₂) cathodes. The resulting cathode materials demonstrate crystallographic integrity and electrochemical performance comparable to those derived from commercial Li sources. By coupling electrochemical control, solution-phase Li leaching, and materials regeneration, this work establishes a process-oriented framework for valorizing Li from primary battery waste and demonstrates a closed-loop Li utilization pathway that bridges recovery and functional material regeneration, highlighting an underexplored opportunity for sustainable Li resource recovery.