The Supercapacitive Property Of MoO_x/PANI Nanocomposites

Molybdenum trioxide(Mo O3) attracted considerable interest as promising supercapacitor electrod material, because of its low cost, environment friendly and high electrochemical activity. Nevertheless, the inherent poor conductivity hinder the application of Mo O3 as supercapacitor, recent studies have report the way to develop the supercapacitivity of Mo O3 through nanoscaling and hybriding. My dissertation aims to achieve good electrochemical property through making Mo O3 compositing with PANI with nanostructure. The work has been done as below:(1) The controllable synthesis of Mo Ox/PANI nanocomposite with different morphology. Mo Ox/PANI nanocomposites with 1D nanostructure are achieved through a chemical oxidative polymerization. Through changing the p H of polymerization reaction, three kinds of morp Hogy have been achieved. Mo Ox/PANI nanotube’ s diameter is about 400 nm with a length of several micrometer. Among the Mo Ox/PANI nanotube-nanorod the large amount is nanorod, a few nanotube appeared with the inner tube diameter of 100 nm. Mo Ox/PANI nanotube with the inner tube diameter of100~200nm,the thickness of the wall of the tube to be 100~200nm.(2) The study of Mo Ox/PANI nanotube’s supercapacitive behavior in netural water electrolyte. As the pseudoreaction happens focused in the potential range of-0.4~+0.4V, the CV curves shows the retangleike shape with bigger capacitance, so-0.4~+0.4V appears to be the most suitable potential window. As the diameter of Li+ is very small, Mo Ox/PANI nanotube has bigger specific capacitance and better rate capacitivity in Li2SO4 compared with K2SO4 and Na2SO4. Mo Ox/PANI nanotube’s specific capacitance keeps 70% after 1000 cycle at 20 m V/s in 0.5mol/L Li2SO4.(3) The influence of Mo Ox/PANI’s morphology and structure to its supercapacitive property. Owing to the hybriding with PANI, the conductivity has been developed, additionally, the nanostructure developed the utilizing of electroactive material, so Mo Ox/PANI nanocomposites’ supercapacitivity developed a lot compared with commercial Mo O3. Among three morphologies of Mo Ox/PANI, nanotube has the biggest specific capacitance along with better cyclic stability.At the scan rate 1m V/s the specific capacitance of Mo Ox/PANI nanotube is 197F/g. When galvanostatic charge-discharge test with the current density of 0.6A/g,the specific capacitance keeps as 50F/g after 400 cycles, the better cyclic stability depends on the nanotube structure can avoid the stress concentration cause the destroy of nanocomposite.(4) The influence of secondary doping to Mo Ox/PANI nanotube’s supercapacitive property. After secondary doping with 0.5mol/L HCl the Mo Ox/PANI nanotube achieves higher specific capacitance and more stable cyclic stability,this mainly attributes to the development conductivity of PANI,the reduce of electron transfer resistance, which can assure the smoothly happening of reoxide reaction. At the scan rate 1m V/s the specific capacitance of nanotube-0.5HCl is 353F/g. When galvanostatic charge-discharge test with the current density of 0.15A/g,the specific capacitance keeps as 100F/g after 300 cycles, 0.6A/g the specific capacitance keeps as 72F/g after 300 cycles.