Constructing defect-rich CoO post smart Li extraction from spent Li-ion battery toward efficient oxygen evolution reaction
Abstract
The recycling of spent LiCoO2 batteries has attracted numerous attentions in view of their environmental and economic values. However, conventional hydrometallurgy strategies for spent LiCoO2 recycling still undergo complicated processes that involve multiple steps, resulting in a high-value metal loss and a low value-added product. Herein, a facile method was developed to recycle lithium and repurpose oxygen vacancy-rich cobalt-based catalysts toward oxygen evolution reaction (OER). By roasting LiCoO2 with ammonium sulfate salt at 975?°C for 120?min, lithium was converted into soluble Li2SO4 and 99.2?% of Li could be preferentially leached by H2O, while cobalt was recycled in the form of highly pure cobalt oxide (M?CoO). Importantly, the M?CoO exhibited an excellent OER activity, superior to the spent LiCoO2, the prepared Co3O4, the commercial RuO2, and most of the reported cobalt-based catalysts. The results confirmed that the outstanding OER activity of M?CoO was originated from the rich surface oxygen vacancy, which facilitated the surface reconstruction to form a highly active layer of short-range order species during OER. This study showcased a novel approach to achieving a priority lithium recovery, coupled with an advanced route for catalyst regeneration, from spent lithium-ion batteries for energy conversion and storage devices.