Directly upgrading spent graphite anodes to stable CuO/C anodes by utilizing inherent Cu impurities from spent lithium-ion batteries

Abstract

Reusing spent anodes is a pivotal step for recycling lithium-ion batteries (LIBs). However, it proves challenging to completely eliminate Cu impurities from spent graphite (SG), which hinders the effective recycling of spent anodes. In this paper, a straightforward air oxidation method is proposed to directly upgrade spent anodes into stable CuO/C anodes by harnessing the inherent Cu impurities in spent anodes. The air oxidation process not only repairs the SG to some extent but also generates uniformly dispersed CuO nanoparticles, which chemically bind with the repaired graphite (RG) through Cu–O–C bonds. The specific discharge capacity of the CuO/RG anode can reach as high as 647 mA h g⁻¹ even after 500 cycles (at 372 mA g⁻¹). In addition, this program is found to reduce energy consumption and greenhouse gas emissions by ∼80% compared to previously reported CuO/C production programs. Clearly, this approach provides a new direction for large-scale recycling of spent LIBs and low-cost production of high-performance CuO/C anodes.