Font Size: a A A

Preparation And Characterization Of Carbon Materials As Electrode Materials For Supercapacitor

Posted on:2012-05-02Degree:MasterType:Thesis
Country:ChinaCandidate:F WangFull Text:PDF
GTID:2212330368996921Subject:Physical chemistry
Abstract/Summary:PDF Full Text Request
Develop high energy, high power density, long cycle life of energy storage device has been super capacitor bounded unremitting efforts direction. Among the various of electrode materials, activated carbon materials have significant advantages for preparing the electrodes, due to their low cost, high surface area and perfect chemical stability. They have been received great attention as electrode materials in the fabrication of supercapacitors.In this paper, porous carbon material with high surface area and different pore structure has been successfully prepared by the Phenolic resin (PF) combining Poly vinyl alcohol (PVA) and KOH as activation agents. Additionally, surface morphologies, structure and specific surface area of the samples were studied by SEM, X-ray diffraction and nitrogen sorption measurements. A new pore-expanding agent based on the PVA and the KOH-PVA-activated subsequent carbonization seems to be an interesting alternative to obtain porous carbons with enhanced properties for supercapacitors.The constant charge-discharge tesing was conducted to research on supercapacitors unit and its electrode with the aids of measurement. At the current density of 120 mA·g-1 in 30% KOH aqueous solution, and the charge-discharge voltage ranged from 0 to 0.8V on the electrochemical test instrument, AK3P-0.30 shows the lowest potential drop and the longest discharge time among all AKxP-y samples, indicating that the equivalent series resistance of AK3P-0.30 is a smaller than that of other samples. The specific capacitance of AK3P-0.30 is 218 F·g-1, which is larger than that of other samples. AK3P-0.30 cativated carbon after 1000 times in the cycle, the specific capacitance of retention rate has been above 99%. Because AK3P-0.30 has micro-mesoporous and uniform porous structure.Thus, AK3P-0.30 may be more promising for supercapacitors electrode applications owing to its ability to store the most energy in 30% KOH aqueous solution.Based on the above experiments, we studied the preparation of activated carbon in the organic electrolyte of the electrochemical properties. We have obtained AK2P-0.30-a activated carbon reducing the activated agent KOH. AK2P-0.30-a of pore size distribution is widely and pore size distribution appears two peaks in the 3-5nm and 10-100nm. AK2P-0.30-a may be more promising for supercapacitor electrode applications owing to its ability to store the most energy in 1 mol·L-1 LiPF6/ (EC+DMC) at the current density of 60 mA·g-1. AK2P-0.30-a exhibites large specific capacitance of 140 F·g-1 in an organic electrolyte of 1 mol·L-1 LiPF6/ (EC+DMC); AK2P-0.30-a shows the specific capacitance of 106 F·g-1 at a current density of 120 mA·g-1, which is higher than the specific capacitance of 72 F·g-1 at a current density of 60 mA·g-1in 1M Et3MeNBF4/PC.We compared the activated carbon in water and organic supercapacitors characterization. In water supercapacitor, AK3P-0.30 the best electrochemical performance of activated carbon, mainly due to the existence of micro-mesoporous structure, which will help store energy in water electrolyte; in organic supercapacitor, AK2P-0.30-a the best electrochemical performance of activated carbon, mainly in the broad pore size distribution, which will help the energy stored in organic electrolyte. The supercapacitors improve the electrochemical performance in different electrolytes, the need to pore size distribution of carbon materials.
Keywords/Search Tags:electric double layer capacitor, activated carbon, poly vinyl alcohol, organic electrode
PDF Full Text Request
Related items