Upcycling end-of-life lithium-ion battery into electrocatalysts - Turning waste into value: A review

The rapid expansion of lithium-ion batteries (LIBs) in consumer electronics and electric vehicles has generated a growing volume of end-of-life batteries, creating both environmental challenges and opportunities for resource recovery. Spent LIBs contain valuable transition metals such as Li, Co, Ni, Mn, and Cu that can be repurposed into functional materials. This review examines the upcycling of spent LIB components into electrocatalysts for renewable hydrogen production, with a focus on catalytic processes including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). This review discusses the composition of spent LIBs and their potential as catalyst precursors, followed by an overview of established recycling approaches including hydrometallurgical, pyrometallurgical, and direct regeneration methods. Emerging strategies such as bio assisted recovery, electrochemical and plasma enabled processes, artificial intelligence driven optimization, and integrated recycling routes are also examined. Key catalyst design concepts derived from battery materials, including multi element synergy, defect engineering, surface modification, and direct transformation of cathode structures, are analyzed in relation to catalytic activity and stability for HER, OER, and ORR. By linking material recovery, catalyst design, and performance evaluation, this review provides guidance for developing scalable pathways to convert battery waste into value added electrocatalysts for sustainable energy and circular resource utilization. This article discusses strategies for converting spent Li-ion batteries into high-value electrocatalysts for hydrogen production and other electrochemical reactions. It summarizes conventional and emerging recycling approaches, including bioleaching, electrochemical recovery, and artificial intelligence-driven optimization. It highlights design strategies of electrocatalysts such as multi-metal synergy, defect engineering, and direct cathode transformation for sustainable, circular-energy applications. • End-of-life lithium-ion battery materials can be directly upcycled into functional electrocatalysts. • Multi-metal compositions derived from spent cathodes enable synergistic catalytic effects. • Defect and surface engineering strategies enhance activity of battery-waste-derived catalysts. • Relithiation approaches enable structural recovery and improved electrochemical performance of LiFePO4. • Low-energy integrated upcycling routes support circularity and scalable catalyst production.