Abstract Directly repairing end‐of‐life lithium‐ion battery cathodes poses significant challenges due to the diverse compositions of the wastes. Here, we propose a water‐facilitated targeted repair strategy applicable to various end‐of‐life batches and cathodes. The process involves initiating structural repair and reconstructing particle morphology in degraded LiMn2O4 (LMO) through an additional thermal drive post‐ambient water remanganization, achieving elemental repair. Compared to solid‐phase repair, the resulting LMO material exhibits superior electrochemical and kinetic characteristics. The theoretical analysis highlights the impact of Mn defects on the structural stability and electron transfer rate of degraded materials. The propensity of Mn ions to diffuse within the Mn layer, specifically occupying the Mn 16d site instead of the Li 8a site, theoretically supports the feasibility of ambient water remanganization. Moreover, this method proves effective in the relithiation of degraded layered cathode materials, yielding single crystals. By combining low energy consumption, environmental friendliness, and recyclability, our study proposes a sustainable approach to utilizing spent batteries. This strategy holds the potential to enable the industrial direct repair of deteriorated cathode materials.
