Preparation And Properties Of Urea-Formaldehyde Resin-Based Carbon Electrode Materials

Urea-formaldehyde resin is an important amino resin,which has a series of advantages,such as low price,wide sources,easy operation and rich nitrogen content.UF has become a hot field of research for the scholars both inside and outside the country,used widely in the field of supercapacitors as carbon materials.However,UF resin has poor thermal stability,which limits its application in the field of supercapacitors.In this paper,the thermal stability of urea-formaldehyde resin-based carbon material was improved by adjusting the ratio of raw materials and concentration of curing,as well as doped heteroatom,and template method.It has achieved the retaining of more porous structure and the larger specific surface area,which obtained urea-formaldehyde resin-based carbon materials with significantly improved electrochemical properties.The main contents of this paper are as follows:1.By adjusting the molar ratio of urea to formaldehyde,urea-formaldehyde resin porous microspheres with different particle sizes were successfully prepared.The crosslinking degree of urea-formaldehyde resin was increased by curing with hydrochloric acid,which result in the improving of its thermal stability during high temperature carbonization,and the reducing of fluidity.After a series of characterization,the cured sample shows the best electrochemical performance with the molar ratio of urea to formaldehyde is 1:0.8.The specific capacitance is 120 F g^-1 at the current density of 1A g^-1,while 63 F g^-11 at 10 A g^-1 with the rate performance of 53%.Therefore,the electrochemical performance of urea-formaldehyde resin-based carbon materials has been significantly improved,showing broad application prospects in the field of supercapacitor electrode materials.2.Urea-formaldehyde/thiourea-formaldehyde copolymer resin was prepared by using UF as carbon source and thiourea as nitrogen and sulfur source.The effects of the introducing of thiourea and the curing concentration of hydrochloric acid on the morphology and electrochemical properties of copolymer resins were investigated by a series of characterization and electrochemical performance tests.When the curing concentration is 2 mol L^-1,the copolymer resin changes obviously in the porous structure and shows the best electrochemical performance in 2 mol L^-1 H₂SO₄ electrolyte.The capacitance is 187 F g^-11 at 1 A g^-1 and 120 F g^-11 at 10 A g^-1,indicating good rate performance with the capacitance retention rate of 64.2%.3.UF was used as carbon source and silica as support which was incorporated into the preparation of urea-formaldehyde resin to maintain the morphology of porous microspheres during high temperature carbonization.Also as a hard template to obtain rich porous structure,which can improve the specific surface area.When the dosage of silica is 1.0 g,the prepared UF resin-based porous carbon microspheres exhibit the best electrochemical performance.At the current density of 0.5 A g^-1,the specific capacitance can reach 227 F g^-1,and it can retain 107 F g^-1 at 10 A g^-1 with good rate performance.It has certain research value in the field of supercapacitors as electrode materials.