Supercapacitors Splash Transition Metal Oxide / Carbon Composite Electrode Materials

The supercapacitor is a new type of electrochemical energy storage devices, contract with the rechargeable batteries and the traditional electrostatic capacitors, it has high power density, high charge /discharge efficiency and long cycle life. The research about the capacitor is concentrated on electrode materia mainly. In this dissertation, two kinds of compound electrode materials which are the Manganese dioxide/Active Carbon and the Manganese dioxide/Carbon Black are synthesized by method of In-Situ process. The study concentrated the preparation,characteristics of electrode material and its influence effects upon the properties of capacitor. The main results are as follows:1. The Manganese dioxide/Carbon-based compound materials synthesized by In-Suit synthesis is applied for the electrode of Supercapacitor. The carbon is coated by the manganese dioxide, so it can make use of the high of carbon-based material and high pseudo-capacitence of the manganese dioxide sufficiently. Researched the effect of annealing temperature, concentration on the capacities properties of pseudo-capacitor. The results show that the specific capacitance for the Manganese dioxide/Active carbon is about 150.8F/g and for the Manganese dioxide/Carbon Black is about 142.3F/g in 1mol/L aqueous Na₂SO₄ through the In-Suit synthesis.2. On the basic of the methods of the materials above, to dope Manganese dioxide/Active carbon physically for improving its electracal performance further. The doped materiasl is prepared through sedimentation transform method and it is obtained sucessfully that Manganese dioxide/Active carbon is doped with Nickel hydroxide and Cobalt hydroxide. meanwhile, the mechanism of doping is analysed primarily. The result show doping Ni(OH)₂ can widen the electrochmical window and increase the special capacitence and doping Co(OH)₂ can decreas the equivlent serial resistor. The electrochemical tests demonstrated the electrochmical window, the special capacitence, equivlent serial resistor is -0.4¹V, 171.4F/g, 6.87 ohm when the doping Ni(OH)₂ mass ratio is 15wt% and the special capacitence, the equivlent serial resistor is 156.1F/g, 3.55 ohm when the doping mass ratio is 9wt%.3. Search for some electrolytes for the In-Suit Synthesized Manganese dioxide/Carbon-based compound materials. It has been found that 1 mol/L Na₂SO₄ is fit for electrolytes of the coupound material. by comparing the electracal characters in different kinds of electrolytes and in different concentrations of electrolytes.In this dissertation, our creative and innovational research in In-Suit synthesis reaction, MnO₂/activated carbon composite electrode materials, and so on, gives some significative results, we hope that will give some elicitation for the further investigation of supercapacitors, although there are still something needed given more research, such as composite electrode of MnO₂/Carbon-based, new current collector, new electrolyte.