Grain-boundary engineering of Ni-rich cathodes prolongs the cycle life of Li-ion batteries

Abstract

Ni-rich layered cathodes (NCM) are appealing for advanced Li-ion batteries thanks to their high-energy density and tolerable cost. Nevertheless, the unfavorable mechanical disintegration coupled with the parasitic reactions greatly deteriorates the electrochemical performance of nickel-rich cathodes, particularly under elevated temperature operation. Herein, a simultaneously Sb-doped and LiSbO₃-coated Ni-rich cathode is synthesized through an in situ co-precipitation strategy. The elongated primary particles with radial arrangement could restrain the formation and propagation of microcracks, enhancing the structural stability. Meanwhile, the ion-conductive LiSbO₃ coating on primary particles endows the cathode with a robust interface that significantly inhibits secondary particle pulverization and electrolyte erosion. Consequently, the optimal cathode LiNi_0.82Co_0.11Mn_0.06Sb_0.01O₂ (NCM-1.0%Sb) exhibits a high specific capacity of 199.6 mA h g⁻¹ at 0.1C and 134.0 mA h g⁻¹ at 10C. Notably, it displays superior cycling stability with 89.3% capacity retention after 500 cycles at 1C and 55 °C in a pouch cell. This work sheds new light on relieving the anisotropic strain of Ni-rich cathodes for long-life lithium-ion batteries.