Optimising the electrochemical properties of LiNi0.83Co0.11Mn0.06O2 via WO3 coating and partial W6+ doping through surface pores

Abstract

High-Ni LiNixCoyMn(1-x-y)O2 is frequently utilized as a cathode active material in electric vehicles because of its high energy density. However, its application is limited by its strong polarisation and low-capacity retention rate. This study found that WO3-modified LiNi0.83Co0.11Mn0.06O2 (NCM831) cathode materials showed very promising electrochemical properties. Results revealed that WO3 was successfully coated onto pristine particles and that W6+ was partially doped into Ni-rich materials through the pores on the surfaces of particles. Moreover, the WO3 coating layer on the surface of NCM831 prevented side reactions between the transition metal and the electrolyte, and the crystal plane spacing increased after W6+ modification. The latter result indicated that W6+ doping benefitted electron transfer and Li+ ion transport. The highest first discharge-specific capacity shown by NCM831 modified with 1% WO3 and the capacity retention rate after 100 cycles at 1C (1C = 200mAg−1) were 187.14 mAhg−1 and 90.76%, respectively. These findings provide insights into the real-world applications of high-Ni ternary cathode materials.