Hydrometallurgical recycling technologies for NMC Li-ion battery cathodes: current industrial practice and new R&D trends

Abstract

The supply chain for raw materials needed to fulfill the demand for lithium-ion battery (LIB) manufacturing is less than certain. With the stress and uncertainty of securing the raw materials, predicted price increases in metals such as lithium and nickel could jeopardize the economics in EV battery production. Lithium-ion battery recycling could help alleviate the demands on critical virgin materials. This would realize a price parity goal, $100 per kW h, for internal combustion engines (ICE) and EVs. Simultaneously, recycling could reduce waste in landfill sites as 1 M tonnes of LIBs are set to retire by 2030. In this context the recycling of LIBs becomes imperative, but this industrial activity must be done in full compliance with sustainability principles. For example, current industrial recycling technologies tend to generate a lot of waste products as only some value metals are recovered while simultaneously tend to be energy intensive with heavy chemical usage and risks of water and soil contamination. In this review we focus on spent nickel-manganese-cobalt (NMC) lithium-ion batteries that currently dominate the EV market examining primarily their recycling by hydrometallurgical processing as this route seems to be the most advocated. Our review compares the different hydrometallurgical process flowsheets seeking to highlight areas for chemical and technological improvement as they are proposed in recent patented R&D developments. The review concludes with the strong endorsement of hydrometallurgy-based direct recycling approach as the most sustainable route.