Highly porous niobium oxide/carbon matrix materials with distinct pseudocapacitive performances in aqueous electrolytes

Abstract

NbO2/porous carbon matrix composite material for supercapacitor application is prepared by a facile sugar blowing method. Owing to the unique porous and intergrowth structure, this material possesses effective electron-ion-conductive-network. Thus, it delivers an impressive capacitance of 261 Fg−1 (686 F cm-3) at 1 A g−1 and 175 Fg−1 (460 F cm−3) at 50 A g−1 in 1 M H2SO4. With a wide potential window of 1.8 V in 1 M Li2SO4, it achieves 184 Fg−1 (484 F cm−3) at 1 A g−1 and 130 Fg−1 (342 F cm−3) at 50 A g−1, respectively. Remarkably, a symmetric two-electrode-cell with this material using 1 M Li2SO4 retains its operating voltage of 1.8 V, delivering 18.2 Wh kg−1 (47.9 Wh l−1) at 810 W kg−1 (2130.3 W l−1), and 10.5 Wh kg−1 (27.6 Wh l−1) at 81000 W kg−1 (213030 W l−1), as well as excellent cyclic capability (>10000 cycles). These interesting performance reveals the significant prospect of this material to be utilized in supercapacitors and other electrochemical devices.