Design of ultrathin carbon-wrapped lithium vanadium phosphate nanoparticles as cathodes for high-performance lithium-ion batteries

Abstract

Lithium vanadium phosphate (LVP) is a commonly used cathode material due to its high energy density, low voltage fade, and stability, making it suitable for use in electric vehicles, portable electronic devices, and grid-scale energy storage systems. However, LVP does have some limitations, including temperature sensitivity and lower efficiency compared to certain other cathode materials. Herein, a carbon-modified LVP (LVP/C) composite is designed for lithium-ion battery cathode materials. The uniquely designed LVP/C demonstrates a flake-like and high-crystal structure LVP with ultra-thin 6 nm carbon coating. On the one hand, highly crystalline LVP can provide stable active sites, and on the other hand, the ultrathin 6 nm carbon-coated sheet-like structure can not only alleviate the volume expansion but also avoid agglomeration. As expected, the specific capacities of the LVP/C-150 and LVP/C-180 samples are found to be 120.535 mAh/g and 35.586 mAh/g at a current rate of 0.5 C, respectively. The LVP/C-150 sample exhibites improved rate performance and cycling stability compared to the LVP/C-180 sample. The outstanding electrochemical performance can be attributed to nanostructure, amorphous carbon, and 6 nm ultra-thin carbon coating. Furthermore, our results suggest that the LVP/C-150 sample has a higher lithium-ion insertion/extraction capacity, which contributes to its improved electrochemical performance.