title: A high energy and power Li-ion capacitor based on a TiO2 nanobelt array anode and a graphene hydrogel cathode.
abstract: A novel hybrid Li-ion capacitor (LIC) with high energy and power densities is constructed by combining an electrochemical double layer capacitor type cathode (graphene hydrogels) with a Li-ion battery type anode (TiO(2) nanobelt arrays). The high power source is provided by the graphene hydrogel cathode, which has a 3D porous network structure and high electrical conductivity, and the counter anode is made of free-standing TiO(2) nanobelt arrays (NBA) grown directly on Ti foil without any ancillary materials. Such a subtle designed hybrid Li-ion capacitor allows rapid electron and ion transport in the non-aqueous electrolyte. Within a voltage range of 0.0-3.8 V, a high energy of 82 Wh kg(-1) is achieved at a power density of 570 W kg(-1). Even at an 8.4 s charge/discharge rate, an energy density as high as 21 Wh kg(-1) can be retained. These results demonstrate that the TiO(2) NBA//graphene hydrogel LIC exhibits higher energy density than supercapacitors and better power density than Li-ion batteries, which makes it a promising electrochemical power source.
authors.affiliation: Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai, 200092, China.
authors.forename: Huanwen
authors.initials: H
authors.lastname: Wang
authors.forename: Cao
authors.initials: C
authors.lastname: Guan
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.forename: Hong Jin
authors.initials: HJ
authors.lastname: Fan
keywords: Li-ion capacitors; TiO2 nanobelt arrays; electrochemical; energy storage; graphene hydrogels; hybrid supercapacitors