Highly Stabilized Ni-Rich Cathode Material with Mo Induced Epitaxially Grown Nanostructured Hybrid Surface for High-Performance Lithium-Ion Batteries

Abstract

Capacity fading induced by unstable surface chemical properties and intrinsic structural degradation is a critical challenge for the commercial utilization of Ni-rich cathodes. Here, a highly stabilized Ni-rich cathode with enhanced rate capability and cycling life is constructed by coating the molybdenum compound on the surface of LiNi_0.815Co_0.15Al_0.035O₂ secondary particles. The infused Mo ions in the boundaries not only induce the Li₂MoO₄ layer in the outermost but also form an epitaxially grown outer surface region with a NiO-like phase and an enriched content of Mo⁶⁺ on the bulk phase. The Li₂MoO₄ layer is expected to reduce residential lithium species and promote the Li⁺ transfer kinetics. The transition NiO-like phase, as a pillaring layer, could maintain the integrity of the crystal structure. With the suppressed electrolyte-cathode interfacial side reactions, structure degradation, and intergranular cracking, the modified cathode with 1% Mo exhibits a superior discharge capacity of 140 mAh g^-1 at 10 C, a superior cycling performance with a capacity retention of 95.7% at 5 C after 250 cycles, and a high thermal stability.