Thin films of nano-pyramid titanium nitride (TiN) were sputtered on 304L steel substrate using DC magnetron reactive sputtering. The symmetric full-cell supercapacitor delivered the typical capacitance of 112 F/g at a current density of 1 A/g and retained 30 F/g at high current density of 20 A/g. The device can be charged and discharged for 30,000 cycles with 92.6% capacitance retained.