Advancing hydrometallurgical recycling of spent lithium-ion batteries: an AI-based readiness and sustainability assessment

Recycling of spent Li-ion batteries presents technical and environmental challenges that must be addressed. The hydrometallurgical route offers greater advantages over pyrometallurgy in obtaining pure products, recovering lithium, and handling feedstocks composed of diverse chemical compositions. However, current technologies still face efficiency, economic feasibility, and environmental issues. New advances are motivated by new battery technologies in the market, efficiency, productivity, and low environmental impact. This literature review aims to comprehensively evaluate current and emerging technologies and rank them as per their technology readiness. We compared ongoing approaches with emerging technologies (e.g., membranes, new adsorbents, deep eutectic solvents, ionic liquids, supercritical fluids, nano-hydrometallurgy, and direct regeneration) reported in the literature focusing on complexity, energy usage, emissions, economic potential, and adaptability. The qualitative analysis was used to rank technologies based on a scoring system. The scoring was obtained using a novel approach utilizing artificial intelligence (AI) models eliminating personal preferences in qualitative data evaluation. The results indicated the technology readiness of the processes: direct regeneration > adsorbent materials > supercritical fluids > deep eutectic solvents > membrane technologies > ionic liquids > nano-hydrometallurgy. Future directions highlight the necessity of testing the identified technologies in emerging battery chemistries (e.g., sodium-ion batteries) to ensure efficient and sustainable recycling processes.