(517n) Recycling of Cathode of Lithium-Ion Batteries: A Unique Application of Oxalate Chemistry

Lithium-ion batteries (LiBs) are used commercially in numerous applications ranging from portable electronics to electric vehicles. The worldwide battery technology market is expected to reach $150 billion by 2025. However, at the end of their life span, LiBs must be sustainably recycled such that they do not end up in landfills. In this work, a closed-loop, sustainable, and green process for separation and recovery of Li and Co from LiCoO₂ using oxalic acid is being developed. Oxalic acid is unique in terms of its reducing, chelating, and precipitating properties. During digestion of LiCoO₂ in oxalic acid, the Co directly precipitates as cobalt oxalate dihydrate (CoC₂O₄·2H₂O), and the Li remains in solution (Li₂C₂O₄) providing an efficient separation. The CoC₂O₄·2H₂O can be converted to cobalt oxide (Co₃O₄) by calcination in air. The Li can be precipitated from the aqueous oxalate phase in the form of a carbonate or phosphate. The remaining oxalate in the filtrate after Li precipitation can be recycled using an acid cation-exchange resin process. The Co₃O₄ and Li₂CO₃ can be used to produce new LiCoO₂ using a solid-state synthesis process. This poster will provide an overview of the entire process, which includes metal extraction, precipitation, and thermal conversion with specific attention towards the regeneration of oxalic acid.