Fabrication and electrochemical performance of nickel oxide nanoparticles anchored titanium dioxide nanotube array hybrid electrode

Nickel oxide-titania nanotube array hybrid grown on titanium substrate (NiO–TiO 2 /Ti) is designed as supercapacitor electrode for energy-storage application. The electroactive NiO is fully incorporated into independent titania nanotubes to form NiO–TiO 2 nanotube array hybrid through differential pulse voltammetry electrodeposition process and thermal dehydration process. NiO nanoparticles are uniformly anchored on TiO 2 nanotube walls to keep open pore mouth of nanochannels. The charge transfer resistance at the interface of electrode/electrolyte is highly declined from 76.3[Formula: see text][Formula: see text] of TiO 2 /Ti to 1.1[Formula: see text][Formula: see text] of NiO–TiO 2 /Ti. The electrochemical performance is highly improved from the electrical double-layer capacitance of 0.16[Formula: see text]mF[Formula: see text][Formula: see text] for TiO 2 /Ti to Faradaic capacitance of 18.75[Formula: see text]mF[Formula: see text][Formula: see text] for NiO–TiO 2 /Ti in 1.0[Formula: see text]M KOH electrolyte due to high electroactivity of NiO. The capacitance retention after 1000 cycles achieves 83.86% for NiO–TiO 2 /Ti and 97.49% for TiO 2 /Ti. The highly electrochemical stability of TiO 2 /Ti contributes to high cycling stability of NiO–TiO 2 /Ti in a continuous charge–discharge process. The superior capacitance of NiO–TiO 2 /Ti nanotube array hybrid is mostly attributed to its accessible redox reactive sites of NiO nanoparticles on TiO 2 nanotube walls. NiO–TiO 2 /Ti nanotube array hybrid can act as a promising energy-storage electrode material.