title: Simple synthesis of amorphous NiWO4 nanostructure and its application as a novel cathode material for asymmetric supercapacitors.
abstract: This study reports a simple synthesis of amorphous nickel tungstate (NiWO4) nanostructure and its application as a novel cathode material for supercapacitors. The effect of reaction temperature on the electrochemical properties of the NiWO4 electrode was studied, and results demonstrate that the material synthesized at 70 °C (NiW-70) has shown the highest specific capacitance of 586.2 F g(-1) at 0.5 A g(-1) in a three-electrode system. To achieve a high energy density, a NiW-70//activated carbon asymmetric supercapacitor is successfully assembled by use of NiW-70 and activated carbon as the cathode and anode, respectively, and then, its electrochemical performance is characterized by cyclic voltammetry and galvanostatic charge-discharge measurements. The results show that the assembled asymmetric supercapacitor can be cycled reversibly between 0 and 1.6 V with a high specific capacitance of 71.1 F g(-1) at 0.25 A g(-1), which can deliver a maximum energy density of 25.3 Wh kg(-1) at a power density of 200 W kg(-1). Furthermore, this asymmetric supercapacitor also presented an excellent, long cycle life along with 91.4% specific capacitance being retained after 5000 consecutive times of cycling.
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
authors.forename: Lengyuan
authors.initials: L
authors.lastname: Niu
authors.forename: Zhangpeng
authors.initials: Z
authors.lastname: Li
authors.forename: Ye
authors.initials: Y
authors.lastname: Xu
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Hong
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
authors.forename: Jinqing
authors.initials: J
authors.lastname: Wang
authors.forename: Shengrong
authors.initials: S
authors.lastname: Yang
mesh_terms: D025802:Electric Capacitance; D004566:Electrodes; D049329:Nanostructures; D009532:Nickel / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D013696:Temperature; D017973:Tungsten Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D017973:Tungsten Compounds; D009532:Nickel; C045951:tungstate