Holistic Bulk-to-Surface Tailoring of Ni-Rich Cathodes for Unlocking Superior Electrochemical Stability

Abstract

Ni-rich cathodes have revolutionized lithium-ion batteries by delivering high energy density. However, achieving a durable trade-off between capacity and long life remains a formidable challenge, hindered by oxygen loss, irreversible phase transformation, and structural degradation during repeated cycles. Herein, we propose a synchronous bulk-to-surface full-scale modification strategy by integrating multi-site B/Ce bulk doping with a conformal CeO2 surface coating. Boron atoms are successfully incorporated into transition metal (TM) tetrahedral interstitial sites as a covalent "rivet" to suppress detrimental H2-H3 phase transitions and anisotropic strain, thereby effectively inhibiting the intra-particle crack propagation. Concurrently, cerium ions are located at TM octahedral sites, acting as an electron buffer to decrease the concentration of reactive Ni4+ species and stabilize the oxygen lattice. Furthermore, the uniform CeO2 protective layer serves as a robust physical barrier against electrolyte corrosion while effectively scavenging acidic species, reducing TM dissolution, and mitigating interfacial side reactions. The comprehensively regulated NCM83 cathode exhibits exceptional electrochemical performance, maintaining 94.4% capacity retention after 1000 cycles at 1 C in a pouch-type full cell. This study presents an innovative approach that combines an internal multi-site lattice with an external surface structure for developing advanced Ni-rich cathodes.