This study presents a one-step, environmentally friendly lithiation process for regenerating spent LFP cathodes under ambient conditions using low-cost reagents, including ascorbic acid. A simplified scheme of the green lithiation process in aqueous solution is illustrated, showing the recycling loop from cathode recovery to regeneration and the formation of new 18650 cells. Regenerated LFP exhibits excellent electrochemical performance after 1000 cycles.

The increasing demand for lithium-ion batteries (LIBs), primarily driven by the expanding electric vehicle market and the growing need for efficient energy storage, presents both significant opportunities and challenges. The efficient and cost-effective regeneration of spent LIBs is crucial to minimizing environmental impact and fostering a true circular economy for battery materials. Herein, an innovative one-step lithiation process is introduced for spent LiFePO₄ cathodes, conducted in aqueous solution under ambient conditions. This method utilizes readily available and low-cost reagents, including a lithium source and ascorbic acid (vitamin C) as a green reducing agent, offering a substantial advantage over traditional techniques that require harsh conditions and complex setups. The lithiation reaction proceeds rapidly, producing pure and fully regenerated LFP. This environmentally friendly process was successfully demonstrated at the scale of 18650 cells with electrodes composed entirely of recycled LFP. These cells exhibit excellent electrochemical performance, even after 1000 cycles at 1C rate, comparable to those made with pristine LFP. By providing a sustainable, cost-effective, and easily scalable solution for LFP cathode regeneration, the approach supports the closure of the materials loop, contributing to the sustainable management of LIBs and advancing the shift toward a circular economy.