Recycling spent cathodes from Li-ion batteries (LIBs) is an appealing route to address environmental issues and resource shortage, but is plagued by effective and simple recycling techniques. Current recycling technologies generally involve multi-steps such as acid leaching, precipitation, smelting, or solid-state sintering, and obtained products possess inferior electrochemical properties. The current work explores a new regeneration method for failed LiCoO₂ cathode material. The electrochemical performance of LiCoO₂ is fully recovered through a single thermal-chemical treatment of spent LiCoO₂ in molten LiOH–KOH–Li₂CO₃ under air atmosphere. The molten salt mixture presents suitable dissolving capacity, homogeneous thermal circumstance, abundant Li⁺, and high ion diffusion rate to decompose impurities, compensate for Li⁺ deficiency, and repair damaged structure through a “dissolution-recrystallization” mechanism. Under the optimized reaction temperature of 500 °C, the regenerated LiCoO₂ possessed similar stoichiometric composition and crystalline structure of commercial LiCoO₂. Importantly, the discharge capacity of spent LiCoO₂ was recovered from 68.3 mA h g⁻¹ to 144.5 mA h g⁻¹, reaching the original level of commercial LiCoO₂. Besides, the regenerated LiCoO₂ also delivered superior cycling of 92.5% capacity retention after 200 cycles and excellent rate performance. This work presents an effective and extendable approach to regenerate spent cathode materials to retrieve their electrochemical performance.

中文翻译：

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一锅式降解LiCoO2的成分和结构再生，可直接将其用作高性能锂离子电池正极

从锂离子电池（LIB）回收废阴极是解决环境问题和资源短缺的一种有吸引力的途径，但是却受到有效而简单的回收技术的困扰。当前的再循环技术通常涉及多个步骤，例如酸浸，沉淀，熔炼或固态烧结，并且所获得的产物具有较差的电化学性能。当前的工作探索了一种用于失效的LiCoO ₂阴极材料的新再生方法。通过对熔融的LiOH–KOH–Li ₂ CO _3中的废LiCoO ₂进行一次热处理，可以完全恢复LiCoO ₂的电化学性能。在空气中。熔融盐混合物具有合适的溶解能力，均匀的热环境，丰富的Li ⁺以及高的离子扩散速率，可以分解杂质，补偿Li ⁺不足并通过“溶解-再结晶”机制修复受损的结构。下的500℃下的优化的反应温度，将再生的LiCoO ₂具有相似的化学计量组成和商业的LiCoO的晶体结构₂。重要的是，废LiCoO ₂的放电容量从68.3 mA hg ^-1恢复到144.5 mA hg ^-1，达到了商用LiCoO ₂的原始水平。。此外，再生的LiCoO ₂在200次循环后还具有出色的循环能力（92.5％的容量保持率）和出色的倍率性能。这项工作提出了一种有效且可扩展的方法来再生废阴极材料，以恢复其电化学性能。