Encapsulating V2O3 nanorods into carbon core-shell composites with porous structures and large specific surface area for high performance solid-state supercapacitors

Abstract

V2O3@C core-shell nanorods with porous structures and large specific surface area were synthesized using V2O5 nanowires as the source of core and glucose as the source of shell by a facile hydrothermal route combination of heat treatment. As-prepared V2O3@C nanorods comprised of core-shell structures with crystalline V2O3 cores and amorphous carbon shells. Nitrogen adsorption-desorption isotherms revealed that V2O3@C core-shell nanorods displayed BET specific surface area as high as 219 m2·g−1 and had hierarchical porous structures. Electrochemical properties of V2O3@C core-shell nanorods as supercapacitor electrode were studied and showed their measured capacitance was based on the pseudocapacitance. Specific capacitances of V2O3@C core-shell nanorods measured 228, 221, 207, 158 and 127 F·g−1 at current densities of 0.5, 1, 2, 5 and 10 A·g−1, respectively. Results showed V2O3@C core-shell nanorods displayed higher specific capacitance than values of carbon spheres (4 F·g−1 at 1 A·g−1) and V2O3 nanomaterials (49 F·g−1 at 1 A·g−1). Asymmetric supercapacitor device assembled from V2O3@C core-shell nanorods and activated carbon (V2O3@C//C) showed specific capacitances of 0.297, 0.274, 0.230, 0.194 and 0.169 F·cm−2 at current densities of 0.5, 1, 2, 5 and 10 mA·cm−2, respectively. It showed higher specific capacitance than that of V2O3//C device (0.219 F·cm−2 at 1 mA·cm−2). A capacitance retention of 86% for V2O3@C//C device after 1000 cycles indicated that V2O3@C had good cycling performance for supercapacitor application. Present findings suggested that V2O3@C core-shell nanorods could be considered as potential materials for high-performance energy storage materials.