Preparation And Electrochemical Tests Of Phenolic Resin Based Carbon Foams

Carbon foam has wide application prospects because of its larger specific surface,higher porosity and excellent electrical conductivity and adsorption characteristics,such as the electrode materials,environmental protection,catalyst carrier and other fields.However,the low energy density of carbon foam limits its commercial development as electrode material.It is now possible to improve the electrochemical properties of porous carbon by combining it with other materials.In this paper,phenolic resin synthesized by phenol and paraformaldehyde as raw material are mixed with the emulsifier,foaming agent and curing agent,to get phenolic foam at the condition of 65 degrees Celsius.Then,the phenolic foam as a carrier,adding the solution of graphene oxide and cobalt acetate,manganese acetate into pores of phenolic foam.Put it in a tubular oven high temperature carbonization after drying in inert gas environment,finally will get porous carbon/graphene,porous carbon/manganese dioxide,porous carbon/cobalt oxide/manganese dioxide composite material.The conclusion is as follows:(1)Phenolic resin was used as carbon precursor and mixed with emulsifier,foaming agent petroleum ether and acid curing agent to synthesize phenolic foam.The optimum preparation conditions were obtained by controlling variables: M(phenolic resin): M(EL20): M(petroleum ether): M(phosphoric acid: benzene sulfonic acid =7:3)= 100:5:8:8 at 65 degrees Celsius.Preparation of phenolic foam with high porosity opening,in response to join the anionic surfactant sodium dodecyl sulfate(SDS).When the quality ratio of SDS and EL20 is 1:3,with good performance foam can be obtained;(2)A certain proportion of graphene oxide is added in the foaming process.Using the interaction between graphene oxide and phenolic foam functional groups,graphene/carbon foam composite can be obtained when carbon reduced graphene oxide in the high temperature carbonization process,.At the scanning rate of 5 mV/s,the specific capacitance can reach 288 F/g,which is about 35% higher than the single phenolic resin based carbon foam capacitor(213 F/g).(3)The phenolic foam wiht high porosity as the carrier,adding cobalt acetate and manganese acetate solution alternately,after absorbing completely and drying,put it into the tube furnace high temperature carbonization,get porous carbon/cobalt oxide/manganese dioxide ternary composites,under 5 mv/s scanning rate,the specific capacitance of 667 F/g,the capacitance of the material performance is greatly increased.It has a good application prospect.