Preparation And Electrochemical Properties Of Nickel Hydroxide Nanocomposites

As a new kind of green energy storage devices,supercapacitor has a broad application prospect in the new energy storage,electric cars and other field,filling the gap between electrostatic capacitor and battery and have become the hotspot in the study of new types of energy storage devices.Electrode materials determine the storage properties of supercapacitor.As a result,the research on supercapacitors storage properties should be based on the appropriate electrode materials.Because of its special structure and morphology,Ni(OH)2 has superior performance in charge storageHerein,we report a simple and efficient strategy to fabricate Ag nanoparticles(Ag NPs),carbon quantum dots(CQDs)and different thickness of PPy decorated hierarchical Ni(OH)2 with lamellar structure.The prepared composite electrode materials were characterized by XRD,SEM,TEM et al.Their electrochemical performances have been evaluated by galvanostatic charge-discharg,cyclic voltammetry(CV),electromical impedance spectra et alHierarchical Ni(OH)2 with lamellar structure was successfully fabricated by a fast,facile and cost-effective hydrothermal method.Electrochemically anodic oxidation of ethanol was used to prepare CQDs,CQDs/Ni(OH)2 was obtained by electrostatic force.The hybrid materials demonstrate excellent electrochemical performance with remarkable specific capacitance and high rate properties.Such remarkable electrochemical properties can be primarily ascribed to the large surface area of hierarchical Ni(OH)2 and the conductivity of the CQDsSilver nanoparticles were grown in situ on the surface of thin layer nickel hydroxide by photoreduction method.The morphology and content of Ag NPs could be controlled by altering the irradiation time at a fixed concentration.Due to the three-dimensional structure of the nanocompisite and the addition of silver particles shortening transmission path of ions and electrons,Ag/Ni(OH)2 showed excellent electrochemical performance.Compared with bare sample,Ag/Ni(OH)2 exhibits a higher specific capacitance of 2176 F g-1 at 1 A g-1 and better rate capability.An asymmetric supercapacitor balanced by Ag/Ni(OH)2 and active carbon(AC)has been successfully assembled,which yields a specific cell capacitance of 206.2 F g-1 at 1 A g-1.Furthermore,it delivers a high energy density of 64.4 Wh kg-1 at a power density of 0.75 kW kg-1 as well as an excellent cycling stability(<4%capacitance loss over 3000 cycles)Multi-lamellar Ni(OH)2@PPy was synthesized by a facile hydrothermal method and in situ polymerization process.The thickness of the PPy has an unusual effect on electrochemical performance was adjusted by varying the concentration of PPy.Own to the synergic effect between Ni(OH)2 and PPy,appropriate PPy coating ensures good electrochemical performance.Ni(OH)2@PPy-0.5 owns the best eletrochemical performance,larger specific capacitance of 2458 F g-1 was obtained at 1 A g-1,doubling the specific capacitance of pure Ni(OH)2 in three electrode system.Ni(OH)2@PPy//AC asymmetric supercapacitor(ASC)exhibits a high specific energy density of 78 Wh kg-1 with a power density of 746W kg-1,95%specific capacitance was obtained after 3000 cycle number,suggesting excellent electrochemical performance.