Restoration of Degraded Spinel Structure from Spent Li-Ion Battery Cathodes towards Reclaiming for Second Life

Abstract

As the volume of discarded Li-ion batteries grows, the need for effective recycling solutions has become crucial for economic and environmental preservation. The direct regeneration of electrode materials from used Li-ion batteries has gained significant attention and is interesting due to its streamlined approach, lower energy consumption, and high cost-efficiency. Typically, the regeneration of depleted cathodes requires a source of lithium to address the lithium loss. The precise management of Li⁺ ion concentrations in the resulting lithium-rich solution can be employed directly to reintroduce lithium into depleted cathodes. This study involves the restoration of lost Li⁺ ions in depleted Ni, Co dual substituted LiMn₂O₄ cathode through aqueous lithiation. The relithiated/regenerated Ni, Co substituted LiMn₂O₄ cathode demonstrates an initial specific capacity of 125.2 mAhg^–1 and 105.5 mAhg^–1 after 500 cycles at a current density of 100 mA with a capacity retention of 84.2%.