Supercapacitor Electrode Nano-materials Research

Supercapacitors is a new type of electrochemical energy storage devices. They have high power density, high charge /discharge efficiency and long cycle life in comparison with rechargeable batteries and traditional electrostatic capacitors. In this thesis, the composite carbon aerogel is investigated for electrode materials of supercapacitors. The studies concentrated on the preparation, characterisation of the composite carbon aerogel electrodes and factors affecting their capacitive properties. The main results are given as follows:(1) Manganese dioxide/carbon composite aerogel by a method of sol-gel process combined with supercritical drying technique were synthesized for the electrodes of supercapacitors. The preparation process of the composite aerogel was investigated and optimized in details. The effects of annealing temperatures, electrolyte concentration on the capacitive properties of the manganese dioxide/carbon composite aerogel electodes were studied. The results show that the specific capacitance is enhanced by the process of supercritical drying. The specific capacitance is about 182.64 F/g in 1mol/L aqueous Na₂SO₄.(2) The vanadium pent-oxide/Carbon aerogel were obtained by the similar method used above for the preparation of the materials of MnO₂/carbon aerogel. The effects of electrolyte variety, concentration on the capacitive properties of the vanadium pent-oxide/Carbon aerogel electrodes were investigated. The electrochemistrical measurements indicated that the specific capacitance is about 173.34 F/g in lmol/L aqueous Na₂SO₄. Additionally, Co₃O₄/carbon composite aerogel were also prepared and characterized electrochemically.(3) Nanocrystalline particles of basic metal oxide (NiO_x, CoOx, V₂O₅) were synthesized by means of anitrate (oxidizing agent)-citrate (organic fuel) gel-combustion process and applied for the electrodes of supercapacitors. The electrochemistrical characterization revealed that the nanocrystalline NiO_x electrode is psuedocapacitive, and the specific capacitance is about 78.7 F/g in 2mol/L aqueous KOH. The particles size of CoOx is around 64.2nm, and its specific capacitance is about 167.5 F/g in...