An in situ formed inorganic conductive network enables high stability and rate capability of single-crystalline nickel-rich cathodes

Abstract

Single-crystalline Ni-rich cathodes are promising for the next generation of high-energy-density Li-ion batteries due to their better capacity retention than their polycrystalline counterparts. However, there is still much room for improving the electrochemical performances when considering their surface degradation and severe kinetic hindrance during cycling. Herein, we report a strategy to construct an in situ formed robust Li-conductive Li₃PO₄ layer on the surface of cathode particles. This Li-conductive layer significantly increases the Li-ion diffusion coefficients and suppresses detrimental surface phase transformation. In situ XRD reveals that the improved kinetics alleviate the local stress at high voltage. The as-prepared single-crystalline LiNi_0.83Co_0.12Mn_0.05O₂ delivers good durability (96.8% after 100 cycles at 1C) and excellent rate capability (177.08 mA h g⁻¹ at 5C). This work provides a facile and efficient strategy to improve the cycling performance and boost the rate capability of single-crystalline Ni-rich cathodes.