Enhanced supercapacitive performance on TiO2@C coaxial nano-rod array through a bio-inspired approach

Abstract A coaxial core–shell structured TiO 2 @carbon nano-rod arrays (TiO 2 @C NRAs) was constructed and tested as a supercapacitor electrode in this study. Dopamine was self-assembled into a polydopamine nano-rod arrays within the TiO 2 nano-tube arrays (TiO 2 NTAs) and was used as a precursor for the carbon nano-rod generation. Electrochemical measurements showed that the electrodes made with coaxial TiO 2 @C NRAs exhibited substantially higher electrochemical performances such as larger areal capacitance and faster charge/discharge capability than those of the pristine TiO 2 NTA electrode and porous active carbon materials. Benefiting from the enhanced electrical conductivity and increased surface area of the coaxial nano-rod structure, the prepared coaxial TiO 2 @C NRAs electrode achieved a remarkable areal capacitance of 40.75 mF cm −2 at a current density of 0.2 mA cm −2 , which was significantly higher than that of the pristine TiO 2 NTAs (0.31 mF cm −2 ).