Improved performance of cylindrical hybrid supercapacitor using activated carbon/niobium doped hydrogen titanate

A cylindrical hybrid supercapacitor is fabricated using activated carbon positive electrode and H(2)Ti(12-x)NbxO(25) (0 <= x <= 0.6) negative electrode materials. The hybrid supercapacitor using H2Ti11.85Nb0.15O25 exhibits the best electrochemical performance. It has a capacitance of 78.4 F g(-1), charge transfer resistance (R-ct) of 0.03 Omega, capacitance retention of 91.4% after 1000 cycles at 3.0 A g(-1) and energy density of 24.3 W h kg(-1) at a power density of 1794.6 W kg(-1). Therefore, the Nb doped HTO negative electrode material is a promising candidate as an energy storage system for electric vehicles (EVs). 2015 Elsevier B.V. All rights reserved.