Scalable upcycling of spent LiNixCoyMn1−x−yO2 to single-crystal Ni-rich cathodes using a low-cost, multifunctional Ni salt

Abstract

The urgent need to recycle spent lithium-ion batteries (LIBs) is driven by the dual pressure of raw material scarcity and ecological sustainability. Closed-loop recycling of spent LIBs not only recovers valuable materials but also minimizes harmful environmental impact, offering an efficient strategy to meet the increasing demand for critical resources. Here, we introduce a thermally driven selective upcycling process that extracts lithium from spent polycrystalline LiNi_0.33Co_0.33Mn_0.33O₂ (NCM111) using NiSO₄. This process subsequently converts the residual materials into single-crystal Ni-rich cathodes with minimal input of nickel and lithium. We demonstrate that both chemically delithiated NCM111 and spent NCM111 black mass can be upgraded in terms of composition, structure, and electrochemical performance to match pristine LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811). Life-cycle analysis reveals that this closed-loop selective upcycling approach significantly reduces energy consumption and greenhouse gas emissions, offering superior economic and environmental advantages over conventional hydrometallurgical, pyrometallurgical, and cathode production methods. This work establishes a foundation for cost-effective upcycling strategies, advancing the sustainable development of NCM materials and selective recovery for LIBs.