Preparation Of Novel Carbon Materials And Their Applications In Electrode Materials

Supercapacitors,as a novel type of energy storage equipment,have the characteristics of high power density,long senice life and large specific capacitance.Polyaniline electrode in pseudo capacitance system is popular for its low cost,simple preparation and good chemical stability.But the polyaniline electrode has the problems of poor circulation stability,low actual capacitance and low conductivity.As a new type of carbon material,both carbon quantum dots and graphene have large specific surface area,which can provide more space for electronic transmission and storage.Carbon materials show good characteristics in electrochemistry.New carbon materials were used into the polyaniline system to prepare composite materials.The synergistic effect between carbon materials and polyaniline was well utilized to improve the electrochemical properties.In this paper,a new type of carbon material with plane-point structure was prepared based on the preparation of carbon dots and the combination of graphene and carbon dots.This kind of carbon material was applied to polyaniline electrode material to improve its electrochemical properties.The main content is as follows:1 Carbon quantum dots were prepared by microwave and electrochemical.The carbon dots were prepared by microwave with propylene tool as carbon source,and the carbon dots were passivated by propylene triol to make the carbon dots have good fluorescence and water solubility.Carbon dots were prepared by electrochemical oxidation with graphite rod as raw material under the condition of electrolysis.By contrast,Carbon dots prepared by microwave method contain more abundant hydroxyl functional groups,and the preparation process is simple and controllable,and the morphology and size of carbon dots can be effectively adjusted.At the same time,the preparation time is short,and large-scale preparation can be carried out,with better application prospects.2 The carbon dots prepared by microwave method was doped into the polyaniline system by in-situ polymerization,and the composite electrode was improved in the aspects of conductivity,specific capacitance and cycling stability.Compared with pure polyaniline at 0.5 A/g current density,the specific capacitance of PANI@25minCQDs composite electrode was improved by 25.12%,and the specific capacity was maintained at 78%after 1000 cycles under 5 A/g current density.3 By using graphene matrix and hydrothennal composite of carbon dots and graphene oxide,a carbon material with a plane-point structure was successfully prepared.Using the size advantage of carbon dots and abundant functional groups,the graphene was modified effectively and the graphene stacking phenomenon was greatly improved.The GO@CQDs composite material prepared has a flatter structure,larger actual specific surface area and better mechanical strength.4 The electrochemical properties of the composite electrode PANI@GO@CQDs were greatly improved after the GO@CQDs was compounded into the polyaniline system.In particular,the electrochemical properties of the composite electrode PANI@GO@30minCQDs were improved by 51.43%compared with the pure polyamiine at the current density of 0.5 A/g,and its cycling stability was kept at 91%compared with that of the capacitor.5 Compared with the composite carbon dots,the addition of graphene provides a more stable carbon structure,which makes the prepared composite electrode P PANI@GO@CQDs have a greater improvement iin electrochemical performance compared with PANI@CQDs.It may be that the relatively large scale stable lamellar carbon structure of graphene plays a key role,and carbon dots,as nano-carbon particles.contribute less to the structural stability than graphene.Figure:[58],Table:[10],Reference:[110].