Purification and regeneration of spent graphite via a short-process combining microwave irradiation and acid leaching

With the rapid development of the electric vehicle market, recycling of spent batteries will undoubtedly become an urgent issue to be addressed. Conventional batteries recycling method regarded graphite as a waste by-product rather than a valuable functional material, leading to its degradation during high-temperature or chemical processes aimed at metal recovery. From the perspectives of environment and economy, recovering graphite from used lithium-ion batteries is of utmost importance. This study presented a microwave-assisted phosphoric acid leaching technique, which can rapidly and economically recovery degraded graphite. The synergistic effects of microwave radiation and mild phosphoric acid leaching could effectively remove metal impurities and repair graphite structural defects, leading to an excellent electrochemical performance. The regenerated graphite providing a reversible capacity of 368 mAh g⁻¹ after 100 cycles at a 0.2C current, with an enhanced capacity retention rate of 99.9%. This technology avoids the traditional energy-intensive graphitization process and the use of strong acid, thus establishing an industrial-feasible and environmentally friendly closed-loop graphite recycling model.