Preparation And Properties Study Of Porous Carbon Materials

The porous carbon material with characteristics of having controllable pore sizedistribution, high surface area, large pore volume, good electrical conductivity andthermal conductivity are widely used in gas separation, purification of water, catalystsupports, electric double layer capacitors, fuel cells, lithium-ion batteries, adsorbents andgas storage and other fields.At present, the methods for the synthesis of porous carbon materials are halogencorrosion, thermal decomposition, supercritical fluid erosion and template method. Thesemethods often have complex process, high requirements for equipment, high reactiontemperature or obtain product of low purity. Such issues seriously hindered the extensiveapplication of porous carbon materials.This paper aims to develope a new method for the preparation of porous carbonmaterial to deal with the problems existing in the current synthesis methods. The mainsubject of the use of molten salt electrolysis method is to study the effect of electrolysistime, temperature, electrolysis voltage and other parameters on the structure andelectrochemical properties of porous carbon prepared. Finally, inorganic salts as atemplate was also applied for porous carbon material preparation, and its properties arestudied. X-ray diffraction, transmission electron microscopy, low temperature nitrogenadsorption, Raman spectroscopy, and constant current charge-discharge test method wereused to characterize the product.The reaction conditions of porous carbon preparation by molten salt electrolysis oftitanium carbide and silicon carbide were:3.1V for the electrolysis voltage,48h forelectrolysis time, and850℃and950℃electrolysis temperature. Molten saltelectrolysis experiments under different temperature were also conducted to investigatethe influence of temperature on the morphologies and electrochemical performances ofporous carbon. X-ray diffraction analysis indicates that the electrolytic products are carbonmaterial. Combined with transmission electron microscopy and Raman spectra results, thecarbon material are composed of amorphous carbon and graphitized carbon composition, and with the increase of temperature, the graphitization degree is strengthened. Lowtemperature nitrogen adsorption test shows that the pore structure of the porous carbon ismainly micropores with pore size distribution mainly in2nm, and the largest specificsurface area is1137.74m2/g. Constant current charge-discharge test at300mA/g showedthat the porous carbon preparaed at950℃has the maximum discharge capacity of161.29F/g. Compared with the molten salt electrical method, inorganic salts templatemethod has many advantages, such as easier after-treatment, shorter experimental period,simplified procedure, higher yield and lower cost, make it more suitable for industrialproduction.