Studies On Nickel-based Electrode Materials For Supercapacitors

The supercapacitor is a new type electrochemical energy storage device between thetraditional dielectric capacitor and the battery. The supercapacitor can provide high energydensity, high power density, long cycle life and less pollution. According to the principle ofenergy-storage there are two types of supercapacitors: electric double-layer capacitor andfaradaic pseudocapacitor. Supercapacitors have achieved much attention in many fields,such as mobile telecommunication, information technology, consumer electronics,aerospace, military force, and so on. Recently, studies on supercapacitors have been mainlyfocused on the preparation of high performance electrode materials. Electrode materialsmainly include carbon materials，metal oxides and conducting polymers （ECP）. As theelectrode composite materials can take advantage of synergies between the variouscomponents to improve overall performance, which is much better than the pure carbonmaterials, oxides and ECP. Therefore, improving electrode composite materials have beenthe main research in the present. Composite electrode materials can be classified into fourcategories: carbon/metal oxides, carbon/ECP, metal oxides/ECP and others. In the presentpaper, the preparation of OMC, temperature, time and loading amount optimization ofOMC/nickel compounds composite material, preparation of binary Ni-Mn （Ni-Fe）compounds/OMC composite. X-ray diffraction （XRD）, N2adsorption/desorption isothermstransmission electron microscopy （TEM）, cyclic voltammetric, cycle life andelectrochemical impedance spectroscopic analyses were used to characterize thecomposites. The main results and innovations are as follows:1. OMC was prepared by using the SBA-15as the template in this rearch. The carbonsources of OMC are sucrose and furfuryl alcohol. The pore size distribution of OMC isnarrow, mean pore diameter is4nm, surface area is1500m2g^-1. The specific capacitanceof OMC is350F g1, when it is measured in2M KOH electrolyte at the scan rate of5mVs1. 2. A series of high performance OMC/nickel compounds composites have beensynthesized by a combination of incipient wetness impregnation and hydrothermal methodfor the first time. The OMC and nickel nitrate hydroxide hydrate composites appear to bepromising electrode materials for pesudocapacitors due to their excellent electrochemicalperformances, environmentally friendly and low cost, whose specific capacitance is1470Fg1. It is to be confirmed that it may open an opportunity to synthesize other novelelectrode materials for supercapacitor.3. The electrochemical behavior of binary Ni-Fe compounds/OMC and Ni-Mncompounds/OMC composites synthesized by a combination of incipient wetnessimpregnation and hydrothermal method for the first time is systematically compared （usingcyclic voltammetric and electrochemical impedance spectroscopic analyses）. Thecomposite materials take advantage of synergies amoung the various components toimprove overall performance.4. It is noted that one new substance MnCO3appeared. The reason is possibly that thecarbon framework supplies the carbon source. The composite contained MnCO3exhibitshigh specific capacitances at various scan rates and have a good retention. Thespecificapacitance of it is380F g^-1, which is1.9times higher than MnO₂/OMC composite(200F g^-1).