Fabrication of nanoarchitectured TiO2(B)@C/rGO electrode for 4 V quasi-solid-state nanohybrid supercapacitors

Abstract

Novel TiO2(B)@C/rGO nanoarchitectures are fabricated by combining hydrothermal treatment, ions exchange, and topological phase transformation as well as carbon modification. Asymmetric hybrid Li-ion nanohybrids supercapacitors with high energy and power densities are constructed by combining hybridized anode, which can supply both pseudo capacitance from TiO2(B) and electrochemical double layer capacitance (EDLC) from nanocarbons (graphene nanosheets and amorphous carbon layer), and activated carbon (AC) as EDLC type cathode. The high power density is realized readily via both the modification of nanocarbons, which not only improve the electric conductivity but introduce extra Faradic capacitance, and the employment of high-voltage formulated ionic liquids electrolyte as well as ionogel polymer separator. Such a balanceable and complementary design between electrode and electrolyte allow rapid ion and electron transport in ionic liquid-based electrolyte and hybridized electrodes. The maximum energy and power density of 59.4 W h/kg and 17.3 kW/kg can be readily realized at 40 °C on account of the special characteristic of ionic liquids. These results clearly demonstrate that high performance nanohybrid supercapacitors can be actualized through the subtle combination of nanohybridized electrodes and high voltage formulated ionic-liquid/lithium-salt electrolytes, which make them promising power-type energy storage devices for hybrid electric vehicles.