Upcycling of High-Rate Ni-Rich Cathodes through Intrinsic Structural Features

The paradigm shift toward the closed-loop recycling of spent lithium-ion batteries necessitates the direct, efficient cathode recovery that goes beyond the traditional pyrometallurgy and hydrometallurgy techniques, meanwhile avoiding substantial energy consumption, tedious procedures, or chemical contamination. In this study, a straightforward, dual-functional upcycling approach is presented for the spent nickel-rich cathodes to boost their high-rate performance. Specifically, the protocol rationally employs the Li vacancy within the degraded oxide to minimize the La diffusion barrier, expanding the lattice spacing of the layered structure; the Li⁺ conductive, conformal LiLaO₂ encapsulation further suppresses the interfacial acid corrosion and structural deterioration into the rock-salt phase. Transmission-mode X-ray diffraction tracks the reversible lattice breathing of the regenerated cathode in operando, suggesting the continuous, kinetically boosted solid-solution process with all the microcracks repaired. The as-assembled regenerated LiNi_0.8Co_0.1Mn_0.1O₂/Graphite pouch cell (1.4Ah) thus achieves 91.0% capacity retention for 500 cycles, the energy density of 277 Wh kg⁻¹ as well as extreme power output of 1030 W kg⁻¹ at the cell level. This upcycling strategy paves the way for value-added utilization of the retired Ni-rich cathodes in practical high-rate battery prototypes.