Carbon nanotubes/graphitic carbon nitride nanocomposites for all-solid-state supercapacitors

All-solid-state supercapacitors with high power density and working stability are high-efficiency energy storage devices for smart electronic equipment. Developing electrode materials with fast ions and electrons transport is critical to improving the energy storage capability. Here, we report carbon nanotubes/graphitic carbon nitride nanocomposites with large specific surface area, porous structure and high electrical conductivity toward high-performance supercapacitors. The large surface area with porosity provides reservoir for ion accommodation during charge-discharge processes, and the high conductivity facilitates electrons and ions transport. Furthermore, nitrogen sites in electrodes contribute significant pseudocapacitance for supercapacitors. The nanocomposites based device gives a high specific capacity of 148 F g ⁻¹ at current density of 1 A g ⁻¹ with good rate capability from 1 to 10 A g ⁻¹. Additionally, the device displays excellent working stability with capacitance retention of 93% even after 10000 cycles at 1 A g ⁻¹ under 0.8 V in air. This study sheds light on design of nanocomposites with highly efficient charge transfer and will accelerate development of next-generation solid state energy devices.