N, S-doped silicon oxycarbide-drived carbon/amorphous ball-flower-like NiO as high performance electrode in asymmetric supercapacitors

Abstract

Efficient utilization for synergistic effect from different electrode materials with optimized structure and composition is a promising strategy to enhance electrochemical performance of composite electrodes. In this work, amorphous ball-flower-like NiO loaded on N, S-doped silicon oxycarbide-drived carbon (NSCDC/NiO) composites with tunable microstructure were synthesized through an easy alkali etching method followed via a hydrothermal method. The synthesized NSCDC/NiO electrodes display a good capacitance (804 F g−1/111.7 mAh g−1 at 1 A g−1) and hopeful cyclic property. Furthermore, the asymmetric supercapacitor (ASC) device assembled using NSCDC/NiO as anode and N, S-doped silicon oxycarbide-drived carbon (NSCDC) as cathode possesses excellent energy density (100.6 Wh kg−1) when the power density reaches 850.2 W kg−1. After 5000 cycles, ASC device has 84.0% retention rate of original capacitance, showing that the NSCDC/NiO composite is a satisfying and promising electrode applied in supercapacitors. The electrochemical properties of NSCDC/NiO composites are greatly improved owing to the excellent electrical conductivity of NSCDC framework, ball-flower-like NiO with amorphous state and hierarchical porous structure, which are beneficial to transportation of ion and electron, reduction of volume change during charge-discharge process.