Facile Utilization of Spent LiCoO2 in Separator Decoration of Lithium-Sulfur Batteries

The increased application of layered oxide (LiCoO2) lithium ion batteries (LIBs) for electronic products will result in lots of spent layered cathodes in the near future. Furthermore, the exploration of a proper recycle strategy becomes an extremely tough challenge. In the traditional hydrometallurgy and pyrometallurgy routes, an atomic-level breakage was involved and required a complex procedure and toxic chemistries, which brought high cost and second environmental pollution. Based on the pioneer application of metal oxides in the separator decoration in high energy lithium-sulfur (Li-S) batteries, an innovative and green strategy has been proposed to directly utilize degraded LiCoO2 through a crystal-nondestructive process. The degraded LiCoO2 was used to modify the separator of Li-S batteries to effectively inhibit the diffusion and promote the conversion reactions of lithium polysulfides (LiPSs), which can be attributed to the derived spinel phases during long-term cycling. The Li-S batteries with spent LiCoO2 show excellent electrochemical performance with a high capacity retention of 74.68% over 200 cycles at 1600 mA g–1 and high discharge capacities of 979.9, 913.7, 847.5, and 758.1 mAh g–1 at 800, 1600, 3200, and 4800 mA g–1, respectively. This study not only provides a high-value application of spent LIBs but also suggests the potential of spinel-structured materials to boost the Li-S batteries.