Preparation oaf polyaniline/diazonium salt/TiO 2 nanotube arrays as supercapacitor electrode by electrochemical grafting and deposition

Polyaniline/diazonium salt/TiO 2 nanotube arrays (PANI/DZ/TiO 2 NAs), as a supercapacitor electrode material, are fabricated by two-step anodic oxidation of titanium foils , electrochemical grafting and reduction of diazonium salts, and electrochemical deposition of polyaniline. Surface morphology, crystallization, and chemical compositions of nanocomposites are characterized by SEM, EDX, XRD, and Raman. Electrochemical tests indicate that PANI/DZ/TiO 2 NAs have excellent capacitance of 1108.5 F g −1 when the current density is 0.6 A g −1 . With the current density increasing 20 times to 12 A g −1 , the capacitance remains about 77.5%, demonstrating its good rate performance. Moreover, after 2000 charge–discharge cycles at 12 A g −1 , the capacitance retains 83.7% of the initial value, showing its good cycling stability.