Preparation Of Phenolic Carbon Aerogel By Solvothermal Method And Electrochemical Performance Study

Supercapacitors are an important energy storage device with the advantages of fast charging and discharging rates and excellent energy storage characteristics.They are widely used in electric vehicles,portable electronics,backup power supplies and military equipment.Carbon materials are one of the most widely used electrode materials for supercapacitors.Phenolic resin is an ideal precursor material for the preparation of high purity carbon.At present,phenolic carbon aerogel is usually synthesized by resorcinol monomer wet gel,which is dried and carbonized by supercritical drying or freeze-drying technology.It has high cost,long cycle and expensive equipment.On the basis of the existing research,this thesis mainly focuses on a method for the preparation of phenolic resin-based carbon aerogel material with simple synthesis process,low cost and good electrochemical performance.By optimizing the hydrothermal synthesis conditions,PF carbon aerogels with good electrochemical properties were prepared.On this basis,the electrochemical properties of phenolic resin carbon aerogels were further improved by GO compounding and nitrogen doping.The main research contents and conclusions of the thesis are as follows:（1）Phenolic resin aerogel blocks were successfully synthesized by simple hydrothermal and atmospheric drying,and PF carbon aerogels were prepared by carbonization.The results show that the microscopic morphology of PF carbon aerogel is spherical particles,which are connected to form a "bead chain" three-dimensional network structure.There are certain cross-links between the spherical particles.With the hydrochloric acid catalyst volume fraction of 9.1%and the solid content of 20%,the PF carbon aerogel prepared in ethanol solvent has the best electrochemical performance,and the specific capacitance at a scan rate of 5 mV s^-1 is 138.33 F g^-1.The method has simple synthesis process and low cost,and the prepared PF carbon aerogel has good electrochemical performance.（2）By using GO as template and melamine as nitrogen source,GO composite and nitrogen-doped PF/GO and PMF/GO carbon aerogels were prepared.The results show that the morphology of the carbon aerogel changed from the microsphere of PF to the lamellar network structure of PF/GO.The phenolic resin polymerized onto the surface of the GO template to form a lamellar structure,and its thickness decreased with the increase of GO addition.The specific capacitance of PF/GO reaches 150 F g^-1,which is 8.4%higher than that of PF carbon aerogel.The specific capacitance of nitrogen-doped PMF/GO carbon aerogel is 216 F g^-1,which is 56%higher than that of PF.But the nitrogen doping content is lower.（3）By using dicyandiamide and 3-aminophenol as nitrogen sources and GO as template,PMAF/GO/DCD carbon aerogels with higher nitrogen doping were prepared.The results show that the nitrogen content of PMAF/GO/DCD carbon aerogel is as high as 1.23%,which is 61.5 times that of PMF/GO.The specific capacitance of PMAF/GO/DCD is 266.43 F g^-1,which is 1.23 times higher than that of PMF/GO.The synergistic effect of stable nitrogen doping and GO recombination enables PMAF/GO/DCD carbon aerogels to have good electrochemical performance.