Critical dual roles of carbon coating in H2Ti12O25 for cylindrical hybrid supercapacitors

The cylindrical hybrid supercapacitors are fabricated using pristine and different coating amounts of carbon (1.5, 3, 4.5, and 6 wt%) coated H2Ti12O25 negative electrode and activated carbon positive electrode to investigate the effect of carbon coating on the electrochemical performances of hybrid supercapacitors. The electrochemical performances of the hybrid supercapacitors indicate that the 4.5 wt% carbon coating layer (approximately 3.09 nm) exhibit the superior electrochemical performances. Moreover, the carbon plays an important role in suppressing the swollen phenomenon. These performances can be attributed to the dual roles of carbon coating, including physical and chemical obstacle and high conductivity pathways. Therefore, we suggest that the carbon-coated H2Ti12O25 negative electrode can be applied to various energy storage devices.