Hybrid dual conductor on Ni-rich NCM for superior electrochemical performance in Lithium-ion batteries

Abstract

To enhance the conductivity of cathode materials, we propose a surface modification of Li_1.03(Ni_0.88Co_0.08Mn_0.04)O₂ (NCM) cathode materials with a high ionic conductor (Li_1.3Al_0.3Ti_1.7[PO₄]_3, LATP) and a high electronic conductor (multi-walled carbon nanotubes, MWCNTs). In this study, a lithium-ion conductor with a structure similar to NASICON was successfully synthesized via a modified Pechini method. For the surface modification, a prepared nanosized LATP and a commercial Ni-rich NCM (Ni ≥80%) were combined by grinding them together. LATP-coated Ni-rich NCM exhibits a high diffusion level (2.144 × 10⁻⁶ cm²∙s⁻¹) in the voltage range of 2.8 to 4.35 V at 25°C owing to increased ionic conductivity. Subsequently, MWCNTs, which are electrically conducting, are coated onto the LATP-coated Ni-rich NCM via a wet process. The electrochemical performance of the MWCNT/LATP dual-coated Ni-rich NCM was evaluated at 25°C and 45°C. The results demonstrate that the dual-coated Ni-rich NCM cathode materials exhibit a high discharge capacity, adequate rate capability, and stable cycling performance.