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

Abstract 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 LiLaO 2 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 0.8 Co 0.1 Mn 0.1 O 2 /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.