Thick electrodes for electrochemical relithiation to regenerate spent battery powder

Abstract

The growing use of lithium iron phosphate (LiFePO₄, LFP) batteries in electric vehicles and energy storage systems highlights the urgent need for efficient and sustainable recycling methods. Direct recovery technologies show promise but often require supplementary lithium chemicals. This study introduces a thick electrode system for the electrochemical relithiation of spent LFP battery powder, utilizing residual lithium from low-grade Black Mass. Unlike previous regeneration techniques, this method eliminates the need for external lithium sources beyond the spent battery powder and the minimal amount of aqueous electrolyte. Our approach overcomes the limitations of traditional electrochemical relithiation by directly processing the spent battery powder without binder, enhancing both industrial scalability and processing capacity. The thick electrode system significantly improves powder recovery capacity, achieving 405 g h⁻¹ m⁻² with low energy consumption (9.3 kWh t⁻¹), and demonstrates excellent performance subsequently. Ecological and economic assessments reveal considerable reductions in the recycling cost and environmental impact.