Critical metal extraction from spent battery cathodes and anticipated developments using next generation green solvents for achieving a net-zero future

The global shift towards decarbonizing the energy sector necessitates the extensive adoption of efficient electrical storage systems, such as Lithium-ion and Nickel-metal hydride batteries. However, these spent batteries pose significant global challenges due to the loss of critical materials and environmental pollution. Effective recycling of spent batteries mitigates pollution, conserves valuable resources, and enhances sustainability. Sustainable battery design involves implementing innovative technologies that promote the efficient and eco-friendly recycling of waste batteries to recover the critical metals. Integrating next-generation green solvents such as ionic liquids and deep eutectic solvents into battery recycling becomes essential to meet the growing demand for critical metals as well to achieve environmental sustainability. This review provides recent technical advances of conventional recycling processes, systematically reviewing the pyro-and hydro- metallurgical processes and emphasized the role of next-generation green solvents in the development of sustainable recycling processes. To further highlight the potential benefits of the new process in terms of its green, low-carbon, low-energy consumption, and reduced toxicity profile, we conducted a comparative analysis of key environmental indicators between conventional and novel processes, emphasizing the role of innovative solutions in promoting sustainable and efficient recycling for a net-zero future.