Carbon-coated sodium vanadium phosphate for high-performance sodium-ion batteries

Abstract

Room temperature sodium ion batteries are feasible for large energy storage equipment because they are both safe and inexpensive. However, the low electronic conductivity of sodium ion battery cathode material is an inherent flaw. Here, the solid-phase carbothermal reduction method was used to create Na3V2(PO4)3/C composites coated with four different carbon sources (Vc, maltose, sucrose, and PEG-2000). XRD and SEM were used to examine the crystal structure and microstructure; the electrochemical properties of four samples were examined using a constant current charge discharge test and AC impedance spectroscopy. As a result, the samples coated with PEG-2000 were identified to have an excellent microstructure and good electrochemical properties. Specifically, the discharge capacity decays from 103.9 mAh/g to 93.4 mAh/g after 340 cycles, and the corresponding capacity retention rate is 89.89%. Moreover, the outstanding electrochemical performance of Na3V2(PO4)3/C composites demonstrates that it is a promising material for the practical application of sodium-ion batteries.