Preparation Of Nitrogen Doped Graphene Quantum Dot Composites Of Supercapacitor

In order it's urgently needs to find advanced environmentally friendly and renewable energy materials to alleviate the pressure on the environment and energy,nowadays,as one of the outstanding representatives of various electronic devices,supercapacitors are pushing people's demand to become smaller and higher power density micro power supplies.Supercapacitors have excellent performance in electrochemical energy storage,and are far larger than batteries in the traditional sense in terms of electrical power and rate performance,and have a higher and wider electrochemical window.In this paper,nitrogen-doped graphene quantum dots are used as reinforcement materials to study the performance of supercapacitors composed of nitrogen-doped graphene quantum dots,polyaniline and reduced graphene oxide composite materials.The specific work is as follows:Firstly,we used the in-situ polymerization method to prepare a nitrogen-doped graphene quantum dot/polyaniline(NGDQs/PANI)composite material as the working electrode of the supercapacitor,and made a series of characterizations.According to the test results of FTIR and XRD,the oxygen-containing functional groups and structural defects on the surface of NGDQs can be seen.Observation results by electron microscopy showed that NGDQs were evenly distributed on the surface of PANI to form a rough granular structure.The NGDQs/PANI composite material does not destroy the structure of PANI,while increasing the specific surface area,thereby improving the capacitance performance and increasing the utilization rate of the material.Electrochemical tests show that as the amount of NGDQs added increases,the specific capacitance of NGDQs/PANI composites tends to increase first and then decrease,reaching a maximum when the content is 2.5%.When the current density is 0.5A/g,a specific capacitance of 506F/g is obtained.When the current density is 5A/g,5000 cycles are passed,and the capacitance retention rate of 80.2% is obtained while maintaining high cycle stability.NGDQs/PANI as an electrode material has good electrochemical performance,which is much higher than PANI's specific capacitance and cycle life,which is valuable for future energy storage development.Secondly,this experiment used ammonium citrate(AC)as the carbon source in the experiment,and graphene oxide(GO)as the raw material.One-step synthesis of NGDQs/reduced graphene oxide(rGO)composites by using in-situ polymerization hydrothermal method.FTIR,XRD,TGA and other characterization results show that the composite material also has more active sites with the addition of NGDQs,and the quantum dots are uniformly compounded on the surface of the matrix,increasing the surface area.The effects of samples with different mass ratios on the electrochemical performance were compared,and the optimal ratio was selected.Through the electrochemical test results,it was found that when the molar ratio of NGDQs to GO is 1:2,it can reach 245.7F/g at a current density of 1A/g.After 1000 cycles,the capacitance retention rate is 84.5%.In addition,we added a method of ex-situ polymerization,and finally tested the electrochemical performance of electrode materials of different preparation methods for comparison.