Atomic layer deposition of ultrafine Pd nanoparticles for enhancing the rate capability of LiNi0.8Co0.1Mn0.1O2 cathode

Atomic layer deposition (ALD) technology has been adopted to obtain the ultrathin coating layer on the surface of LiNixCoyMnzO2 (NCM) cathode materials. However, the as-reported coating materials usually form dense film layers and present low electronic conductivity, leading to poor electrochemical kinetics. Herein, the ultrafine Pd nanoparticles (~ 5 nm) with superior electronic conductivity are successfully deposited on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM811) particles by ALD technology. Benefiting from its high electrical conductivity, intrinsic electrochemical inertia to Li+ and HF, unique point coating, and the interfacial Pd–O bond, the coating of ultrafine Pd nanoparticles significantly weakens the electrochemical polarization and enhances the rate capability of NCM811 cathode. The capacity retention ratio at 1 C after 100 cycles reaches 84.6%, and the capacity of 153.5 mA·h·g−1 is realized at 5 C. Further research finds that the battery with the coating layer of 5 deposition cycles has a better electrochemical performance than the batteries with 2 and 8 deposition cycles. This work enriches the application of ALD technology in the surface modification of electrode materials and broadens the mind of electrochemical performance enhancement.