Highly‐Dispersed Submicrometer Single‐Crystal Nickel‐Rich Layered Cathode: Spray Synthesis and Accelerated Lithium‐Ion Transport

Abstract For conventional polycrystalline Ni‐rich cathode material consisting of numerous primary particles in disordered orientation, the crystal anisotropy in charge/discharge process results in the poor rate capability and rapid capacity degradation. In this work, highly‐dispersed submicron single‐crystal LiNi0.8Co0.15Al0.05O2 (SC‐NCA) cathode is efficiently prepared by spray pyrolysis (SP) technique followed by a simple solid‐state lithiation reaction. Porous Ni0.8Co0.15Al0.05Ox precursor prepared via SP exhibits high chemical activity for lithiation reaction, enabling the fabrication of single‐crystal cathode at a relatively low temperature. In this way, the contradiction between high crystallinity and cation disordering is well balanced. The resulted optimized SC‐NCA shows polyhedral single‐crystal morphology with moderate grain size (≈1 μm), which are beneficial to shortening the Li+ diffusion path and improving the structural stability. As cathode for lithium ion batteries, SC‐NCA delivers a high discharge capacity of 202 and 140 mAh g−1 at 0.1 and 10 C, respectively, and maintains superior capacity retention of 161 mAh g−1 after 200 cycles at 1C. No micro‐crack is observed in the cycled SC‐NCA particles, indicating such single‐crystal morphology can greatly relieve the anisotropic micro‐strain. This effective, continuous and adaptable strategy for preparing single‐crystal Ni‐rich cathode without any additive may accelerate their practical application.