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

Implementing a stable interfacial architecture with augmented conductivity emerges as a pivotal approach for bolstering the stability of LiNi _0.5Co _0.2Mn _0.3O ₂ (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 LiCoO ₂ & Li ₃BO ₃ (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.