A green chemical protocol for the separation of spent LiFePO4 cathode material from Al foil and regeneration

Abstract

The recovery and reuse of electrode materials from spent lithium-ion batteries are crucial for the sustainable development of the lithium-ion battery industry. In this study, we describe an aqueous solution-based protocol for separating the LiFePO₄ cathode material from the Al foil (current collector) of spent lithium-ion batteries and regenerating it. The LiFePO₄ cathode material and the Al foil separate effectively from each other on immersing the spent electrode in pure water at room temperature. The recovered Al foil remains in the metallic state. The as-separated LiFePO₄ suffers from lithium loss, ∼34%, and accompanying capacity fading. After a lower-temperature and aqueous-based relithiation, the regenerated LiFePO₄ exhibits electrochemical performance comparable to the commercial one, delivering an initial charging capacity of 162 mAh g⁻¹ at 0.1C, a charging capability of 118.5 mAh g⁻¹ at 5C, and 89.3% capacity retention after 500 cycles at 1C. This facile separation and regeneration strategy represents a sustainable and economic approach for the recovery of spent LiFePO₄.