This paper presents the fabrication of yolk-shell V 2 O 5 powders with a low melting temperature of 690°C by using a simplified two-step process. The spherical V 2 O 3 -C composite obtained by spray pyrolysis transforms into yolk-shell V 2 O 5 powder by a simple combustion process at 400 °C. The yolk-shell V 2 O 5 powders are composed of nanoplate crystals several tens of nanometers in size, and have a BET surface area of 15 m 2 g -1 . The powders exhibit initial discharge and charge capacities of 271 and 264 mA h g -1 at a current density of 1000 mA g -1 , respectively, and a corresponding Coulombic efficiency of 97.4%. After 100 cycles, the discharge capacity of the yolk-shell V 2 O 5 powders is 201 mA h g -1 . In contrast, spherical V 2 O 5 powders with a dense structure exhibit low initial discharge and charge capacities of 160 and 145 mA h g -1 , respectively. The structural stability of the yolk-shell during Li-ion insertion and extraction improves the electrochemical properties of the V 2 O 5 powders, even at high current densities.
ASJC Scopus subject areas
- Materials Science(all)