Adaptive Localized Ectopic Structure Enhances Regeneration of Spent Lithium-Ion Battery Cathodes

Direct regeneration has emerged as a budding strategy for recycling spent lithium-ion batteries, yet restoring the degraded crystal structure of the cathode remains a momentous handicap. Here, a novel deep eutectic solvent rich in lithium (Li) is developed that not only induces the formation of an adaptive local ectopic structure (ALES) characterized by disordered and localized cations, but also facilitates the separation of cathode sheets and replenishes depleted elements. Within ALES, ectopic cobalt (Co) sites boost Li⁺ diffusion by expanding the Li slab and forming octahedral coordination with low-spin Co³⁺, while ectopic Li modulates Co─O interactions, collaboratively impeding long-range structural disorder, mitigating lattice stress, and reducing charge density fluctuations. The synergistic interaction between the ectopic Co and Li enables in situ structural repair of spent lithium cobalt oxide (LCO), thereby restoring crystallinity and enhancing electrochemical performance. The regenerated LCO delivers a reversible capacity of 183.08 mAh g^-1 at 0.2 C, with 87.01% capacity retention after 200 cycles at 0.5 C, outperforming commercial counterparts. This study offers a new pathway for addressing an urgent bottleneck in structure-targeted LIB regeneration.