Acid-Assisted Separation of Cathodic Material from Spent Electric Vehicle Batteries for Recycling

Abstract

The recycling of lithium-ion batteries presents challenges due to the complex composition of waste streams generated by current processes. Achieving higher purity levels, particularly in the reclamation of aluminium metal and transition metal black mass, is essential for improved valorisation. In this study, we propose a high-efficiency, low-energy, and environmentally friendly method using organic acids to separate cathodic black mass from the aluminium current collector. The acids selected in this study all show >86% peeling efficiency with acetic acid showing 100% peeling efficiency of black mass from the current collector. The recovered materials were subjected to X-ray diffraction, electron microscopy, and elemental analysis techniques. We show that oxalic-acid-treated material exhibited two distinct active material components with a minimal change in mass ratio compared to the untreated material. We show by elemental analysis of the leachates that the majority of critical materials were retained in the black mass and limited aluminium was leached during the process, with almost 100% of Al recovery achieved. This methodology enables the production of high-purity concentrated aluminium and critical metal feedstocks (Mn, Co, Ni, and Li) for further hydro-metallurgical processes, upcycling of the cathode material, and direct recycling. The proposed approach offers significant potential for enhancing valorization in lithium-ion battery recycling, facilitating efficient separation and optimal recovery of valuable metals.