| Super capacitors,as a new type of energy storage equipment,are widely used in many fields,such as energy storage systems for hybrid vehicles and computer electronic equipment,due to their fast charging and discharging,high power density,and long cycle life.and many more.According to the different energy storage mechanism,it is mainly divided into electric double layer energy storage and pseudocapacitor energy storage..For carbon materials,a high specific surface area and a stable and reversible redox reaction with electrolyte ions are the key to their use as supercapacitor electrode materials.In general,the specific capacitance provided by the pseudo-capacitor is much larger than that of the electric double layer capacitor,but the electrode material of the pseudocapacitor itself has poor conductivity and poor cycle stability,which limits its application.How to maximize the advantages of the electric double layer capacitance and pseudocapacitance characteristics of carbon materials is one of the problems to be solved urgently for the electrode materials of carbon-based supercapacitors.Ladder Polymer materials synthesized with hydroquinone and formaldehyde as raw materials have many advantages such as high specific surface area and abundant surface oxygen-containing functional groups.They have the characteristics of electric double layer capacitors and pseudocapacitors,which shows great potential in energy storage devices.But its poor conductivity makes its supercapacitor’s performance unable to be exerted to a greater extent.Similarly,graphene oxide is also a pseudo-capacitive electrode material with great potential.The conductivity after treatment under a certain temperature is much higher than that of carbon nanoribbons due to its structural characteristics.The disadvantage is that graphene is easy to agglomerate under the action of vander Waals force,which greatly reduces the specific surface area,which also limits its application as an electrode material.the graphene oxide was synthesized by the modified Hummers method,and then mixed with a certain amount of H3PO4 solution,heat-treated at 250 ℃ for 30 minutes.Subsequently,electrochemical performance tests were conducted in KOH and H2SO4 solutions,and specific capacitances of 150.86 and 143.12 F/g were obtained at a sweep rate of 5 m V/s,respectively,and showed good rate performance.We adopt a simple solvothermal synthesis method of one-step hydrothermal condensation polymerization to form trapezoidal polymer,using hydrochloric acid as a catalyst,formaldehyde and hydroquinone as monomers,to prepare trapezoidal polymer of uniform size and complete structure at 180℃.After being infiltrated with H3PO4 solution,it was carbonized at 400-700℃ for 1 h under the protection of Ar gas.The electrochemical performance test was carried out,its capacitance performance is best at 500℃.Therefore,15 min,30 min and 45 min heat treatments were carried out on the basis of this temperature and compared with the group with a time of 1 h.After analyzing the electrochemical performance,the highest specific capacitance value was obtained under heat treatment at 500℃ for 30 min.Specific capacitance values of 163.22 and 130.27 F/g(Sweep rate is 5 m V / s)were obtained in KOH and H2SO4 electrolytes,respectively.Cycling 10,000 times under the current density of 5 A/g,the capacitance retention rates were 92.8% and 93.1%,respectively,showing excellent cycling stability.The ladder polymer/graphene oxide composite electrode material was synthesized in situ using a one-step hydrothermal method.The rich surface oxygen-containing functional groups of the two were used to achieve good recombination under the action of hydrogen bonding.A set of electrode materials containing 4.0 mg/ml graphene oxide loading was tested for electrochemical performance,and specific capacitance values of 199.5 and 281.0 F/g were obtained at 5 m V/s and 1 A/g,and showed excellent pseudocapacitance. |
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