Surface engineering with bifunctional layer in LiNi0.5Co0.2Mn0.3O2 for high-performance cathode materials of lithium-ion batteries

Abstract

Implementing a stable interfacial architecture with augmented conductivity emerges as a pivotal approach for bolstering the stability of LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) and facilitating expedited Li⁺ transport. To augment efficiency and foster compatibility with industrial processes, a novel one-step, high-temperature modification technique is introduced for the fabrication of a dual-layer LiCoO₂ & Li₃BO₃ (LCO/LBO) coating on the NCM523. This is achieved through the utilization of nano-CoB particles (nCoB) as a medium to capture LiOH impurities. The special coating architecture not only propels Li⁺ diffusion at the interphase but also mitigates acid-induced corrosion, thereby preserving the structural integrity of cathode material throughout its operational lifecycle. Owing to this innovative coating, the electrochemical attributes of NCM523 witness significant improvement, demonstrated by a remarkable 98.2% capacity retention following 100 cycles at 1 C, and a sustained 75.9% capacity retention after 300 cycles, a stark contrast to the 29.2% observed with uncoated NCM523. This investigation validates the LCO/LBO coating paradigm as a means to synergistically enhance Li⁺ translocation across the electrical double layer while countering cathodic structural erosion, offering fresh perspectives in the domain of NCM523 cathode surface enhancement.