Abstract
Supercapacitors as a new type of energy storage devices bridging the gap between conventional capacitors and batteries have aroused widespread concern. Herein, binder-free titanium nitride (TiN) thin film electrodes for supercapacitors prepared by reactive magnetron sputtering technology are reported. The effect of N-2 content on the supercapacitor performance is evaluated. A highest specific capacitance of 27.3 mF cm(-2) at a current density of 1.0 mA cm(-2), together with excellent cycling performance (98.2% capacitance retention after 20,000 cycles at 2.0 mA cm(-2)) is achieved in a 0.5 M H2SO4 aqueous electrolyte. More importantly, a symmetric supercapacitor device assembled on the basis of TiN thin films can deliver a maximum energy density of 17.6 mWh cm(-3) at a current density of 0.2 mA cm(-2) and a maximum power density of 10.8 W cm(-3) at a current density of 2 mA cm(-2) with remarkable cycling stability. As a consequence, TiN thin films demonstrate great potential as promising supercapacitor electrode materials.