A three-in-one strategy for lithium recovery and upcycling of spent cathode materials

The recycling of spent lithium-ion batteries is essential for sustainable development of clean energy industry. Traditional recycling methods face challenges such as high energy/chemical consumption and limited adaptability. This study introduces a ‘Three-in-One’ strategy that leverages mechanochemical (MC) treatment to enhance lithium recovery, transition metal upgrading, and CO₂ sequestration. MC treatment induces micro-segregation of lithium and transition metals, resulting in a structurally disordered material with a Li-rich surface, facilitating selective lithium extraction. Subsequently, CO₂ is used as the sole reagent and lithium leaching efficiency exceeding 95% is achieved by forming lithium bicarbonate. Conducted under ambient conditions without additional grinding aids or leaching reagents, this method minimizes environmental impact. Transition metals are simultaneously transformed into high-performance oxygen evolution reaction (OER) catalysts, demonstrating an overpotential of 322 mV at a current density of 10 mA cm^-2. These catalysts maintain stability over 200 h of operation. This approach not only provides an efficient pathway for lithium recovery but also upcycles spent cathode materials into valuable catalysts, supporting sustainable energy conversion technologies. The strategy is particularly effective for high-Ni cathode systems, offering significant practical advantages.