Molybdenum doping and MoSi2 coating for enhancing electrochemical performance of LiNi0.6Co0.1Mn0.3O2.

MoSi 2 has a low density, high conductivity, and anti-fluorine structure. Therefore, we prepared MoSi 2 -modified LiNi 0.6 Co 0.1 Mn 0.3 O 2 (NCM613) materials by a solid-state method using the precursors of MoSi 2 and NCM613. Analysis using XRD, HRTEM, SEM and XPS reveals that a small amount of Mo from MoSi 2 was doped into the NCM613 lattice, and the rest MoSi 2 was coated on the material surface. DFT calculations show that Mo atom doping preferentially replaces Ni sites in the NCM613 transition metal layer to form more Ni2+. The capacity retention of the best modified sample NCM-0.5MoSi 2 is 74.1% (from 174.0 to 129.0 mAh·g−1) after 300 cycles at 1 C, while the pristine material NCM-0 is only 49.6% (from 171.5 to 85.1 mAh·g−1). Furthermore, the lithium-ion diffusion coefficient of NCM-0.5MoSi 2 is 3.44 × 10−12 cm2·s−1, higher than 2.73 × 10−12 cm2·s−1 of NCM-0. Improved electrochemistry results from Mo doping and MoSi 2 coating, where Mo doping expands the lattice parameters of NCM613 and MoSi 2 coating protects NCM613 from hydrofluoric acid (HF) corrosion. This work achieves the dual effect of Mo doping and MoSi 2 coating through the modifier MoSi 2 , and provides a reference scheme for the improvement of other cathode materials. [Display omitted] • MoSi 2 -modified NCM613 material was prepared by solid-state method. • Dual effects of Mo doping and MoSi 2 coating achieved by modifier MoSi 2. • XPS combined with DFT further studied the mechanism of Mo doping. • MoSi 2 coating plays a dual role of high conductivity and anti-fluorine structure. • The capacity retention of NCM-0.5MoSi 2 is 74.1% after 300 cycles at 1 C. [ABSTRACT FROM AUTHOR]