Super Ion Capacitors Composite Carbon Airgel Electrode Characteristics

The super-ionistor is a new type of electrochemical energy storage devices between the typical rechargeable batteries and the typical dielectric capacitors.It has the advantages of both of them.The typical rechargeable batteries can provide high energy densities, but the low power densities and short cycling life. The typital dielectric capacitors can provide high power densities and have very long cycle life, but the low energy densities. Super-ionistors can meet both the power and the energy requirements systems such as acceleration power for electric vehicles, burst power for the generation of electronic devices and so on, and have drawn more and more attertion in recent years. The compound carbon aerogel is elected as electrode materials of the super-ionistor in this thesis. The study concentrates the preparation,characteristics of electrode material and its influence effects upon the properties of capacitor. The main results are as follows:1. The carbon / nickel oxide compound aerogels are obtained by sol-gel, aging, supercritical drying in CO2, annealing. The content and structure of the compound aerogels are investigated by means of low-temperature N2 adsorption, FTIR spectrum, XRD, SEM, TEM, and SAXS etc. 2. On the basic of the Diffusion Limited Cluster –Cluster Aggregation (DLCA ) model, the influences of the density and energy distribution of sol particles on initial state of sol-gel process are considered. The growth of RF aerogel fractal has been simulated by computer and the growing mechanism of aerogel fractal structure has been studied also. RF aerogels is a kind of nanoporosity materials growing by fractal. Fracral dimension of aerogels is about equivalent at the same density. When low energy. The aerogels grows in the way of a cross-linked network in nanometer scale and it is homogeneous. 3. A composite electrode material comprising nickel oxide/carbon aerogels are synthesized by sol-gel, supercritical drying, aging. The effects of the content of catalyzer and nickel oxide, aging temperature, drying means and so on on the capacitor properties are studied. The mechamism of forming capacitance is also discussed. The results show that specific capacitance decreases when the aging temperature increases from 700℃ to 900℃. With the content of catalyzer and nickel oxide increasing, specific capacitance also add. The specific capacitance up to 162F/g in nickel oxide10%, it is about 260F/g in 1mol/l aqueous KOH in nickel oxide 40%. Equivalent series resistance (ESR) is very low when the mass of nickel oxide is less than 30%. 4. The super-ionistor is provided with high reversible and typical capacitance performance through cyclic voltammetric. AC impedance analysis is employed to study frequency-response characteristic of super-ionister. The super-ionistors doesn't display capacitance at high frequency range.