Study On Preparation And Supercapacitor Performance Of Nickel Series Metal Oxide Nanomaterials

Electrochemical capacitors?ECs?,also known as supercapacitors,have recently been identified as promising energy storege system candidates because of their combination of high energy density and moderate powder density.Different from Li-ion battery,supercapacitors feature fast energy intake and delivery and almost unlimited cyclability,and are therefore adopted to meet civil transportations consumer electronic products and back-up power supplies.In this paper,NiO,Ni3V2O8 and P-doped NiO nanomiterials were prepared by electrospinning technology and studied their electrochemical performance.The main results are summarized as follows:The hollow NiO nanofibers were prepared via a facile yet efficient procedure involving electrospinning of a template PAA nanofiber and subsequent adsorption and annealing of metal ion precursors.The fiber struture was reserved in the material after thermal treatment,whereas the average diameter of the nanofibers changed from²00nm of the template PAA nanofiber to⁸0 nm of the hollow NiO nanofibers.The prepared highly crystallized hollow NiO nanofibers consist of nanosided NiO particles with diameters varying from 10 to 30 nm.The electrochemical measurements demonstrated that NiO nanofibers had a ultrahigh specific capacitance?610 F/g at a current density of 5 A/g?and excellent cycling stability?the retention96%of initial specific capacitance after 5000 cycles at 5 A/g?.One-dimensional Ni₃V₂O₈ nanofibers were prepared by a simple and efficient electrospinning technique and subsequent annealing process.X-ray diffraction?XRD?,Thermogravimetric analysis?TGA?,Field-emission scanning electron microscopy?FESEM?and transmission electron microscopy?TEM?were employed to systematically characterize the crystal structure and morphology of Ni₃V₂O₈nanofibers.The results of XRD,EDS and TGA together confirmed that the pure Ni₃V₂O₈ have been obtained.The FESEM and TEM observation represented Ni₃V₂O₈powder possesses 1D nanostructures with diameters varying from 200 to 300 nm and have a narrow partical size distribution ranging from 20 to 25 nm.The electrochemical measurements indicated that Ni₃V₂O₈ nanofibers had a ultrahigh specific capacitance?1152 F/g at a current density of 1 A/g,1345 F/g at a different scan rate of 5 mV/s?and excellent cycling stability?the retention 84.08%of initial specific capacitance after 2000 cycles at 2 A/g?.The unique structure of Ni₃V₂O₈nanofibers can enhance mechanical stability and electrochemical properties including electrical/ionic conductivity.P-doped NiO nanomaterials were prepared through the electrospinning and investigated the general trend of the influence of electrochemical performance by different P doping content.The results of XRD analysis showed that the intensities of the diffration peaks increased with the decrease of P content.In addition,the diffration peaks of NP_1-1,NP_2-1,NP_3-1,NP_4-1 and NiO could be assigned to standard PDF card of NiO.However,the NP1-1 product exhibited a high background lacking any Bragg reflections.Morphogy characterizations revealed that NP_1-1,NP_2-1,NP_3-1had internal porous structure.However,NP4-1 and NiO samples only exhibited one dimensional structure but not internal porous structure.Amount all products,NP2-1exhibited highest specific capacitance?912 F/g at a current density of 20 A/g?and excellent cycling stability?the retention 96.5%of initial specific capacitance after1000 cycles at 20 A/g?.