Preprints of Annual Meeting of The Ceramic Society of Japan<br> Preprints of Fall Meeting of The Ceramic Society of Japan

We successfully prepared poly(phenylsilsesquioxane) particles, one of the organic-inorganic hybrid materials, by two-step acid-base catalyzed sol-gel process. However, the structure and formation mechanism of the particles were not fully understood. In this study, the structure and formation process of the particles prepared by two-step acid-base catalyzed sol-gel process have been investigated. Moreover, poly(phenylsilsesquioxane) particles have been prepared with different amounts of ethanol used as a solvent, and the average molecular weight of the particles has been decreased with an increase in the amount of ethanol.

View full abstract

Hydrophobic silica aerogels were prepared from methyltrimetoxysilane (MTMS) by the two-step sol-gel method using oxalic acid and ammonium hydroxide as catalysts, and characterized. The specific surface area, porosity and pore size distribution depended on the preparation conditions such as concentrations of MTMS and catalysts. The microstructure was observed by TEM. The grain size also depended on the MTMS concentration. The aerogel with the largest surface area and porosity was obtained using methanol (MeOH) solutions of high concentration MTMS, MTMS:MeOH=1:14 in mol. Effects of MTMS concentration and acid concentration on the microstructure of the aerogel have been discussed.

View full abstract

Platy manganese oxides were used for electrochemical capacitor. Platy fine particle (PF) was prepared by acid treatment of LiMnO2. Platy particle (PL) was prepared by heat treatment and acid treatment of KMnO4. And then, low crystallinity powder (LC) was used for a reference one. The obtained samples (100mg) were pressed 10 mm pellet with 4 mg Ketjan black (KB) and 10 mg PTFE. And cyclic voltammetry measurement was performed to these samples. PL showed a same capacity as LC. PF sample has low capacitance compared with other samples. Using small amount pellet (25mg), PL sample showed higher capacitance than LC. As a result, the interlayer of PL effects to increasing capacitance because of high reaction area and field.

View full abstract

Show abstractHide abstract

Amorphous manganese oxide applied in electrochemical capacitors as electrodes are cheaper than used traditional metallic oxide, but amorphous structure will cause manganese oxides easily to be dissolved in the electrolyte and the capacitance will lower after using for a period of cycles. For stabilization the characteristic of capacitor, it is necessary to precede heat treatment, but it will induce the decrease in capacitance. A novel synthesis technique which is hydrothermal electrochemical deposition method was used for preparation manganese oxide films by can improve these issues. There are many deposition variables such as concentration of electrolyte, hydrothermal temperature, deposition voltage and deposition times influence the specific capacitance. The optimal the synthesis conditions and each factor contribution to the specific capacitance were approaching by using Taguchi experimental design method. In this study, represented the high concentration of electrolyte and lower deposition temperature showed the optimal specific capacitance of ca. 90.30 mF(cm2)-1. The contribution rate of hydrothermal temperature and electrolyte concentration are 39.45%, 30.82%, respectively. The manganese oxide electrodes surface morphology, crystalline structure synthesized by various conditions were also investigated in this study.

View full abstract

Register with J-STAGE for free!