Upcycling of Mixed Spent Cathodes into High-Energy Cathode Materials via an Efficient Leaching–Sol–Gel Strategy

Lithium-ion batteries have been widely deployed in the electric vehicle sector, as well as in other application areas. This widespread use has led to the accumulation of large quantities of diverse spent batteries, particularly lithium iron phosphate (LFP), and the recycling of spent batteries is increasingly imperative. Considering the high economic value of the regenerated lithium manganese iron phosphate (LMFP) product and the coexistence of spent LFP and spent lithium manganate oxide|lithium manganese oxide, we propose a new one-step strategy with integrated leaching–sol–gel and subsequent annealing. Through this route, we can successfully prepare LMFP with high phase purity and structurally stable characteristics. The regenerated LMFP exhibits excellent electrochemical performance, delivering an initial discharge capacity of 162 mAh g–1 at 0.1 C and retaining its capacity without observable degradation after 500 cycles at 1 C. This recycling strategy demonstrates high energy efficiency, economic feasibility, process simplicity, and scalability, highlighting its strong potential for practical application in lithium-ion battery recycling.