Towards a direct recycling approach for complex Li/Na ion cathode mixtures: a selective leaching approach to separate...

The rapid growth in the demand for and use of Li/Na ion batteries will ultimately lead to a significant number of waste cells when they reach the end of their life, requiring recycling to reclaim valuable resources. Commonly, the first stage of the battery recycling process involves shredding to liberate the materials for further processing. In cells where blended electrodes are common, or where cross-contamination occurs from the shredding of different cell chemistries, direct recycling - where the framework of the material remains intact - becomes increasingly more challenging. Here, we report a potential strategy for dealing with such complex mixtures, highlighting a selective leaching approach that can allow the selective separation of a commercial Na-ion cathode material (NFM: NaNi_1/3Fe_1/3Mn_1/3O₂) from a mixture with a commercial Ni-rich NMC (83% Ni) (NMC: LiNi_0.83Mn_0.06Co_0.11O₂) cathode material. A simple ascorbic acid treatment selectively dissolves the NFM, leaving the NMC as a solid (attributed to the higher Mn content of the former), allowing the subsequent direct recycling/regeneration of the NMC, along with the short loop recycling/regeneration of the NFM. The directly recycled NMC is of high quality, preserving the morphology of the pristine material and exhibiting performance matching it. The NFM sample was also successfully regenerated from the leachate via a short loop approach, although further optimisation is required here to match the performance of pristine NFM.