Hydrocarbothermal Reduction Co‐Upcycling of Spent Lithium‐Ion Batteries via Waste Plastics for Enabling Efficient Water Purification and Lithium Resource Recovery

The upcycling of spent lithium‐ion batteries and waste plastics is critical for resource security and sustainable development. However, current recycling paradigms treat these waste streams separately, leading to energy‐intensive battery recovery and low‐value plastic downcycling. Here, we present a waste polyethylene‐driven hydrocarbothermal reduction strategy for upcycling spent LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622 ) cathodes by exploiting the dual functions of plastics as in situ carbon sources and reducing agents, making a breakthrough on their co‐processing and joint upcycling, and constructing a closed‐loop system integrating mixed‐waste upcycling, water purification, and lithium recycling. Hydrocarbothermal reduction via polyethylene pyrolysis induces pronounced interlayer expansion and octahedral distortion within NCM 622 , triggering structural collapse and driving the formation of a stable NiCoMn alloy nanorod deposited on a carbon nanosheet (NiCoMn/C) catalyst. Kinetic analysis shows that Co sites act as the primary catalytic centers, while Ni and Mn mediate charge transfer. NiCoMn/C enables efficient peroxymonosulfate (PMS) activation for bisphenol A degradation with a rate constant of 0.411 min −1 , demonstrating competitive catalytic performance among reported alloy–carbon catalysts. Meanwhile, this system achieves 87% lithium recovery, reduced greenhouse gas emissions, and strong economic viability. This work establishes a generalizable paradigm for integrated waste‐to‐resource conversion and environmental remediation.