Hierarchical porous TiO2/carbide-derived carbon for asymmetric supercapacitor with enhanced electrochemical performance

Abstract Spherical titanium oxide/carbide-derived carbon (TiO2/CDC) composite materials with hierarchical structure were produced by a solvothermal method. CDC materials were generated by high-temperature etching of SiOC, and TiO2 microspheres grew evenly on the CDC surface. The synthesized TiO2/CDC materials for supercapacitors show a significant improvement in electrochemical properties with a good specific capacitance (173.2 F g−1 at 1 A g−1) and excellent cycle stability (82% maintenance of capacitance) in the three-electrode system. Furthermore, the asymmetric supercapacitors (ASC) were constructed by using hierarchical porous CDC and TiO2/CDC as the negative and positive electrode, respectively. The ASC device can keep the original capacitance of 85.1% after 5000 cycles and shows an outstanding long cycle life. The ASC device shows a good energy density (10.76 Wh kg−1 at 4.50 kW kg−1) owing to the combined function of the pseudocapacitive material and a wider potential window from asymmetric supercapacitors, which reveals its great potential application in energy storage devices.