Effective regeneration of LiCoO2 from spent lithium-ion batteries: a direct approach towards high-performance active particles

Abstract

With the growing applications of lithium-ion batteries (LIBs) in many areas, their recycling becomes a necessary task. Although great effort has been made in LIB recycling, there remains an urgent need for green and energy-efficient approaches. Here we report a non-destructive approach to regenerate cathode materials by hydrothermal treatment of cycled electrode particles followed by short annealing. Unlike the conventional chemical leaching or solid-state synthesis approach, which either requires complicated steps of leaching, precipitation and waste treatment or relies on the chemical analysis of the Li/Co ratio from cell to cell, our non-destructive approach is much simpler and more environmentally friendly, and can easily process batteries with different capacity degradation conditions. In addition, the regenerated LiCoO₂ particles can retain their original morphology and structure, and provide high specific capacity and cycling stability. Importantly, they show much better rate capability than particles regenerated through the solid-state synthesis approach. Our work demonstrates a greener, simpler and more energy-efficient strategy to recycle and regenerate faded LiCoO₂ cathode materials with high electrochemical performance. This approach can be widely used to recycle and regenerate LiCoO₂ cathodes on a large scale, and can be potentially applied to other types of cathode materials in LIBs and mixed cathode chemistry.