Recycling of Lithium from Cathod of Lithiumion Batteries using Direct Lithiation

The increasing deployment of lithium-ion batteries (LIBs), particularly lithium iron phosphate (LiFePO₄, LFP) systems, necessitates the development of efficient and sustainable recycling methods. Conventional recycling approaches are often energy-intensive, multi-step, and economically unfavorable for LFP materials. In this work, a simple, low-cost, and environmentally sustainable strategy for the regeneration of spent Li₁₋ₓFePO₄ cathodes is presented. The process involves delamination of the cathode material via water treatment, followed by two regeneration routes: (i) direct re-lithiation using a lithium-based eutectic solvent composed of lithium acetate and ethylene glycol in the presence of organic reducing agents, and (ii) a two-step oxidative leaching using FeCl₃ followed by reductive re-lithiation. Among the reducing agents evaluated, hydroquinone demonstrated superior redox reversibility and regeneration efficiency. The direct re-lithiation process, performed under ambient conditions, successfully restored the olivine LiFePO₄ structure with minimal structural degradation. Electrochemical evaluation revealed significantly improved discharge capacity and cycling stability compared to the spent material. In contrast, the two-step approach resulted in lower electrochemical performance and increased process complexity. The proposed method offers a scalable, energy-efficient, and sustainable pathway for LFP recycling, contributing to the advancement of circular battery technologies.