The direct regeneration of spent cathodes stands out as an environmentally and economically benign strategy within the battery ecosystem, eclipsing the cumbersome metallurgical approaches. Before addressing the lithium loss and structural degradation, it is crucial to focus on the residual contaminants within the spent cathode collected from retired Li-ion batteries after industrial exfoliation processes. Here, comprehensive characterizations and calculations show that in contrast to metal scraps, the electrolyte decomposition after battery operation and heating exfoliation uniformly coat the particle surfaces of cathodes, severely impeding the reuse and rejuvenation of LiNi_xCo_yMn_zO₂ (NCM) cathodes with limited degradation by obstructing lithium diffusion. Considering the high costs and environmental risks of organic systems, we further propose a minute-level water-based pretreatment to purify the spent cathode and selectively eliminate these stubborn impurities that can deteriorate the interfacial chemical state, even after prolonged high-temperature heat treatment. Combined with a solid-state regeneration process, a purified 250k-miles-serviced (8 year) cathode could be rejuvenated to match the pristine one's capacity and cycling retention, displaying a 1.9-fold increase in average lithium diffusivity for charging and 43% enhanced capacity retention after 200 cycles compared with the unpurified one. Our study underscores the critical role of previously overlooked chemical residuals in facilitating the practical direct regeneration of retired lithium-ion batteries.

中文翻译：

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通过分钟级清洗去除残留污染物，有助于从退役 EV 锂离子电池中直接再生废阴极


废阴极的直接再生在电池生态系统中是一种环境和经济上无害的策略，使繁琐的冶金方法黯然失色。在解决锂损失和结构降解问题之前，关键是要关注工业剥离过程后从退役锂离子电池中收集的废阴极内的残留污染物。在这里，全面的表征和计算表明，与金属废料相比，电池运行和加热剥落后的电解质分解均匀地覆盖在阴极的颗粒表面，严重阻碍了 LiNi_xCo_yMn_zO₂ 的再利用和再生（NCM） 阴极通过阻碍锂扩散而进行有限降解。考虑到有机系统的高成本和环境风险，我们进一步提出了一种微小的水基预处理，以净化废阴极并选择性地去除这些顽固杂质，这些杂质即使在长时间的高温热处理后也会恶化界面化学状态。结合固态再生过程，纯化的 250k-miles 服务（8 年）阴极可以恢复活力，以匹配原始阴极的容量和循环保持率，与未纯化的阴极相比，200 次循环后，用于充电的平均锂扩散率增加了 1.9 倍，容量保持率提高了 43%。我们的研究强调了以前被忽视的化学残留物在促进退役锂离子电池的实际直接再生方面的关键作用。