A green recycling process for spent lithium-ion batteries with extremely low chemical consumption

Selective recovery of lithium from spent cathodes is an attractive, green and efficient recycling method for spent lithium-ion batteries (LIBs). However, current technologies face numerous challenges including high reagent consumption, limited versatility and significant secondary pollution. In this study, we found that an intermediate phase formed during leaching exhibited high physiochemical stability, which hindered leaching of Li⁺ and led to increased reagent and energy consumption. A simple mechanical activation strategy was used to change the intermediate phase of the leaching process by activating the spent cathode without grinding additives. The energy input of the mechanical force resulted in defects in the activated waste, leading to a novel activated intermediate phases. Through experimental characterization and DFT analyses, this novel intermediate phase containing H⁺ was found to have a large specific surface area, large internal stress and low reaction energy, which enabled the leaching of the Li⁺. As a result, the method showed a high utilization efficiency of H⁺ in recycling most spent cathodes. In the end, we established a closed-loop recovery route for spent LIBs that exhibited exceptional efficiency for H⁺ utilization (> 97%), obviated the need for auxiliary reagents, and substantially reduced secondary pollutant generation.