Capacitive performance of molybdenum nitride/titanium nitride nanotube array for supercapacitor

Molybdenum nitride (MoNx) depositing on titanium nitride nanotube array (TiN NTA) was designed as MoNx/TiN NTA for supercapacitor electrode material. MoNx/TiN NTA was fabricated by electrodepositing molybdenum oxide onto titanium dioxide NTA and one-step nitridation treatment in ammonia. MoNx/TiN NTA involved top-surface layer of MoNx nanoparticles and underlying layer of TiN NTA, which contributed to electric double layer capacitance in aqueous lithium-ion electrolyte solution. The specific capacitance was increased from 69.05 mF cm−2 for TiN NTA to 121.50 mF cm−2 for MoNx/TiN NTA at 0.3 mA cm−2, presenting the improved capacitance performance. MoNx exhibited the capacitance of 174.83 F g−1 at 1.5 A g−1 and slightly declined to 109.13 F g−1 at 30 A g−1, presenting high rate capability. MoNx/TiN NTA exhibited the capacitance retention ratio of 93.8% at 3.0 mA cm−2 after 1000 cycles, presenting high cycling stability. MoNx/TiN NTA could act as a promising electrode material of supercapacitor.