Water-Induced Integrated Regeneration of Cathode Materials from Spent Sodium-Ion Batteries

The increasingly accumulated end-of-life batteries require high-efficiency regeneration technology for sustainable development. However, the existing recycling methods are highly restricted in a direct additive process due to the inconsistent content of alkaline ions within various spent materials and then failure to recover them together. Here, a subtractive process is introduced for the integrated regeneration of spent cathode materials, which successfully transforms the cathode materials with an unknown Na⁺ content to the desodiation phase together via water only. Because water and Na salt in NaOH solution are reused together after enough CO₂ is absorbed, the regeneration process exhibits net zero emission and ∼100% recovery efficiency. Meanwhile, the regenerated materials display a similar cyclability to the pristine ones, while the former reserves 50.2% of production costs and half of the production time compared to the coprecipitation method. Furthermore, the integrated regeneration of single and polycrystals at various states as well as their mixtures is also verified following the same route. Accordingly, the water-induced subtractive process achieves the integrated recycling of end-of-life sodium-ion batteries and promotes the scale-up application and sustainable development of green energies.