Upcycling Spent LiCoO 2 Batteries Into Heterostructured CoP 2 /Co 3 O 4 for Efficient Oxygen Evolution Reaction

ABSTRACT The widespread application of lithium‐ion batteries in electric vehicles has caused a rapid rise in spent battery accumulation, bringing serious environmental pollution and health risks. Conventional recycling methods, including pyrometallurgy, hydrometallurgy, and direct recycling, suffer from complex processes, high energy consumption, secondary pollution, and low economic benefits. Herein, we propose an upcycling strategy to convert spent LiCoO 2 into high‐value CoP 2 /Co 3 O 4 electrocatalysts, in which Li is extracted via a low‐temperature solid‐state redox reaction combined with water leaching, and Co is converted to CoP 2 /Co 3 O 4 through phosphidation. The catalyst delivers favorable OER performance with an overpotential of 280 mV at 10 mA cm −2 , outperforming commercial RuO 2 , providing a promising approach for high‐value recycling of spent LIBs.