Reviving and Upgrading Storage-Degraded Nickel-rich Cathode via Solid-State Electrolyte Coating

Abstract

Large-scale production of nickel-rich cathodes inevitably results in severe storage degradation (forming surface lithium impurities and NiO rock-salt phase) under humid air conditions that precludes their direct use in battery manufacturing industry.Herein, we propose a facile remediation strategy for storage-degraded LiNi 0.9 Co 0.05 Mn 0.05 O 2 cathodes via a wet-chemistry-assisted Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) coating approach followed by calcination under O 2 atmosphere. During calcination, surface lithium impurities are consumed, Ni 2+ is re-oxidized to Ni 3+ , and Li/Ni disorder is reduced, thereby regenerating the ordered layered structure.Meanwhile, the uniformly formed LLZTO coating serves as a fast Li + conductor and a protective barrier against electrolyte corrosion, suppressing interfacial side reactions and accelerating lithium-ion transport. The repaired cathode not only recovers its performance but even outperforms the pristine cathode. At 200 mA g -1 , the capacity retention of the repaired cathode is 94.9% after 100 cycles, compared with 84.4% for the pristine cathode. The capacity at 4C rate also increases by 18.38%. Post-cycling characterizations confirm a stable layered structure, thinner cathode-electrolyte interphase, lower impedance, and no obvious microcracks after remediation strategy.This work provides a practical solution for reutilization of storage-degraded nickel-rich cathodes, contributing to cost reduction and resource sustainability in battery production.