Preparation And Electrochemical Performance Of Aerogel-based Supercapacitors

At present,environmental pollution caused by the rapid consumption of fossil fuels has prompted that people are becoming more and more interested in new energy sources.The development of wind energy,hydroelectric power,solar energy,biological energy and some new types of energy storage develop rapidly.As a new type of energy storage device,supercapacitors get people’s attention due to their excellent performance.Carbon-based materials are considered to be the main electrode materials for energy storage in supercapacitors,and carbon-based materials with 1D,2D and 3D micro/nano structures have been extensively reported.However,1D and 2D materials have limited specific surface area.3D network aerogel morphologies are a framework containing interconnected micro-/nanosheets while also possessing hierarchical pores on micro,meso,and macro scales.The micro and mesopores structures contribute to the high specific surface area and the macropores provide accessibility to the active surfaces.Based on the above analysis,the research content of this paper is as follows:（1）Using chitosan（CS）and graphene oxide（GO）as precursors,a lightweight,directional structure of 3D network system chitosan-graphene（CS-rGO）composite material is constructed and used as a binder-free aerogel-based electrode for assembled supercapacitor.CS-rGO aerogel electrode with directional porous structure has good electron conductivity and high ionic conductivity.（2）Using the composite aerogel CS-rGO material as the substrate and potassium permanganate（KMn O₄）as the manganese source,the CS-rGO@Mn O₂ aerogel electrode material was synthesized by a simple one-step hydrothermal method.The KMn O₄ of 10 m M,the reaction time of 5 h,and the KMn O₄ concentration of 10 m M were used to obtainα-Mn O₂ nanowires.The size of the nanowires is about 50 nm.Nanowires can reduce the diffusion resistance of the electrolyte very well,and the Mn O₂ nanowires have great adhesion on the CS-rGO composite material so that electrons can be quickly transferred to the current collector.At the same time,CS-rGO is used as a substrate,with high specific surface area and high conductivity.The rate and layered porosity show high volume capacitance and excellent rate performance.（3）We explored the composite electrode material by using transition metal oxide V₂O₅.Using V₂O₅ powder and H₂C₂O₄·2H₂O as precursors,the effect of different hydrothermal reaction time which we get the V₂O₅ nanosheet structure.The obtained nanosheet structure effectively reduces the diffusion time of electrolyte ions and improves the electrochemical performance of the CS-rGO@V₂O₅ electrode material,so that we have obtained high ionic and electronic conductivity and good chemical stability of the material.Through the composite with CS-rGO aerogel material,we have obtained high specific surface area and porosity,which improves the performance of the electrode.