Anchoring Nickel and Stabilizing Oxygen in Coherent LiNiO₂@LiFePO₄ Composite Cathode Materials for Rechargeable Lithium-Ion Batteries.

Abstract

LiNiO₂ is an appealing cathode material for Li-ion batteries because of high energy density and low cost but suffers from irreversible phase transition and surface instability. Herein, a ball-milled LiNiO₂@LiFePO₄ composite with oriented coherent combination is reported with enhanced structural stability and Li⁺ diffusion. The coherent oriented channels are demonstrated to favor the reversible and rapid Li⁺ intercalation during the H2-H3 phase transition, which significantly alleviates structural strain accumulation. The covalent P─O bonds anchored on the LiNiO₂ surface stabilizes the Ni sites, mitigating surface reconstruction and lattice oxygen loss. The LiNiO₂@LiFePO₄ cathode exhibits a specific capacity of 210 mAh g^-1 and an initial Coulombic efficiency of 93.7% at 0.1 C, along with a remarkable rate capability of 156 mAh g^-1 at 10 C. Furthermore, the full cells pairing LiNiO₂@LiFePO₄ cathode and graphite anode deliver a considerable energy density over 280 Wh kg^-1 and a remarkable capacity retention. This study offers an effective approach of phosphate coalesce to upgrade high-capacity nickel-rich oxide cathode materials.