Synthesis Of Polyanilines/Inorganic Nanocomposites And Their Performances In Supercapacitor

As a new type of energy storage devices,supercapacitors?SCs?become the dominating power source,attributing to their fast recharge ability,high power density,good rate performance and long lifespan,which fill the gap between batteries and conventional dielectric capacitors.Electrode material,the most crucial factors restricting performance supercapachor,in particular,nanomaterials with high electrochemical capacitance performance due to short electron-ion transport,has been a hot area of research.This thesis focuses on the research about binary metal oxides-polyaniline nanocomposites including preparation,characterization and supercapacitor performance,the main work and innovation are the following:1.The NiMoO₄ nanorods have been successfully synthesized via a facile glycol-assisted solvothermal approach with a subsequent calcination process.Subsequently,using aniline as the monomer,clubbed NiMoO₄/PANI nanocomposites were prepared by in-situ oxidation polymerization in the presence of NiMoO₄ as a matrix.The structure and morphology of the NiMoO₄/PANI nanocomposites were further characterized by XRD,XPS,BET,FT-IR,FE-SEM,TGA and TEM measurements,which showed core-shell structure and were superior to the specific surface area of pure NiMoO₄.Through electrochemical test,the NiMoO₄/PANI electrode exhibited a high specific capacitance of 1214 Fg^-1 at a current density of 1Ag^-1,which was higher than that of the pure NiMoO₄ electrode(768 Fg^-1).when the current density increased to 20 Ag^-1,the values of capacitance still reached 813 Fg^-1,maintaining capacitance retention of 67%.Satisfyingly,the result was superior to the pure NiMoO₄ electrode?57%?.In addition,the NiMoO₄/PANI electrode exhibits80.7% capacitance retention after 2000 cycles using galvanostatic charge-discharge cycling techniques.2.Using aniline as the monomer,lignosulphonate as the dopant,the Bi₂MoO₆/PANI was deposited to Bi₂MoO₆ nanoflowers were prepared by in-situ oxidation polymerization in the presence of Bi₂MoO₆.The Bi₂MoO₆/PANI nanocomposite affords a large reaction surface area,an excellent structural stability,a large number ofactive sites,good strain accommodation and fast electron and ion transportation compared with pure Bi₂MoO₆,which all are beneficial for improving the electrochemical performance.We investigated the influence of Bi₂MoO₆ amount in the nanocomposite on the electrochemical properties of Bi₂MoO₆/PANI.Among them,the BMP-2 electrode shows a high specific capacitance of 826 Fg^-1 at a current density of 1 Ag^-1,which is higher than pristine Bi₂MoO₆ and other electrodes.In addition,a all-solid-state asymmetric supercapacitor?ASC?has been designed with the BMP-2 electrode as the anode,the AC film on Ni foam as the cathode,KOH-PVA as the solid electrolyte.The ASC device displays a high specific capacitance and perfect cycle performance in a voltage window of 0-1.6 V.3.The hierarchical NiCo₂O₄@NiWO₄ core-shell nanowire arrays?NWAs?by an improved two-step hydrothermal process on Ni foam followed by an annealing process in air.Subsequently,a conducting polymer of PANI interweaved with NiCo₂O₄@NiWO₄ core-shell NWAs and finally the highly ordered 3D hierarchical NiCo₂O₄@NiWO₄@PANI ternary core-shell NWAs were obtained.In addition,this method not only can ensure good mechanical adhesion and electrical connection between the current collector and products,but also avoid the use of polymer binder and conductive additives,and then improve the utilization of the electrode material to gain high capacitance even under high current densities.Impressively,the NiCo₂O₄@NiWO₄@PANI NWAs electrode exhibits superb capacitive behavior as well as good cycling stability(a highest capacitance of 1741 Fg^-1 at 1 Ag^-1 and capacitance loss of 4.8 % after 5000 cycles at 5 Ag^-1).Furthermore,a all-solid-state asymmetric supercapacitor was assembled by Ni Co₂O₄@NiWO₄@PANI and AC electrodes.In case of a power density of 400 W kg^-1,the as-fabricated ASC device can achieve a maximum energy density of 48.2 Wh kg^-1.