Waste to Treasure: Regeneration of Porous Co-Based Catalysts from Spent LiCoO2 Cathode Materials for an Efficient Oxygen Evolution Reaction

The increasing demand for portable electronic devices and electric vehicles (EVs) has triggered the rapid growth of the rechargeable Li-ion battery (LIB) market. However, in the near future, it is predicted that a large amount of spent LIBs will be scrapped, imposing huge pressure on environmental protection and resource reclaiming. The effective recycling or regeneration of the spent LIBs not only relieves the environmental burdens but also avoids the waste of valuable metal resources. Herein, a porous Co9S8/Co3O4 heterostructure is successfully synthesized from the spent LiCoO2 (LCO) cathode materials via a conventional hydrometallurgy and sulfidation process. The fabricated Co9S8/Co3O4 catalyst exhibits high catalytic activity toward oxygen evolution reaction (OER) in an alkaline solution, with an overpotential of 274 mV to achieve the current density of 10 mA cm-2 and a Tafel slope of 48.7 mV dec-1. This work demonstrates a facile regeneration process of Co-based electrocatalysts from the spent LiCoO2 cathode materials for efficient oxygen evolution reaction.