Development of a scalable graphite regeneration process for recycled lithium-ion battery anodes

Graphite remains the predominant material for negative electrodes in lithium-ion batteries (LIBs), maintaining a 98% market share due to its stable operating potential and high theoretical specific capacity. With the growing demand for LIBs in hybrid and electric vehicles, sustainable solutions such as recycling are critical for reducing raw material resource demand and environmental impact. This study focuses on developing a versatile graphite regeneration (pre-purification) process flow that can be applied to various graphite-rich feedstocks from spent LIBs, including direct recycling of end-of-life commercial EV anodes and recovery from black mass. The regeneration process integrates scalable and industrially applicable chemical, thermal, and mechanical treatments under mild conditions in order to purify graphite particles and assess their suitability for reuse as battery-grade material. The regeneration process effectively removes several contaminants including Al, Cu, Ti, Ni, Mn, and Co, yielding purified graphite with carbon content exceeding 97.5%. The refined graphite exhibits robust battery performance when tested in full cells against NMC 622 cathode, reclaiming 96% of the specific capacity of similar cells made with commercial natural graphite and demonstrating a capacity retention of 86.7% after 350 cycles at 1C. This study highlights the potential of the regeneration approach to produce premium-quality recycled graphite close to battery applications, although further optimization and scale-up are required to achieve full industrial viability.