Preparation Of Porous Carbon Nanomaterials And Its Application In Supercapacitors

In recent years,the energy crisis and environmental problems have been widely concerned by the society,and the design of energy storage devices with high efficiency and environmental protection is becoming more and more important.Among various energy storage methods,ultracapacitors have attracted extensive attention due to their high power density and fast charge and discharge speed.The core of the supercapacitor is the electrode material.As an electrode material,carbon material is used in supercapacitors due to its low cost,good electrical conductivity and good physical and chemical stability,and has become a hot spot in the field of materials.However,many defects such as hydrophobic surface and low capacitance of carbon materials hinder the commercialization process.So,in order to realize the commercialization and multi-functionality of the use of carbon materials,it is necessary to make full use of the advantages of carbon materials and to develop carbon materials having excellent electrochemical properties.In view of the above shortcomings of carbon materials,the carbon materials are doped with a conductive polymer polyaniline,nitrogen-doped carbon nanomaterial,and use waste latex sponge trim to synthesize S,O doped carbon materials.A series of porous carbon materials with unique morphology and excellent electrochemical properties were synthesized by the above three methods.The structure and electrochemical properties of porous carbon materials were characterized by various analytical methods.It includes the following three parts:?1?Preparation of porous carbon nanosheet/polyaniline composite and its application in supercapacitors.Three-dimensional interconnected porous carbon nanosheets/polyaniline nanowires?PC/Pani?were prepared by an inexpensive,efficient and simple method and used as high-performance supercapacitors electrodes.PC/Pani hybrids can be prepared by in situ growth of Pani on PC with a high specific surface area and good electrochemical performance fabricated via one-step thermal pyrolysis potassium citrate.In a three-electrode system,the PC/Pani capacitance is 512 F·g^-1 when the current density is 1 A·g^-1,which is mainly due to the synergy between PC and Pani.In addition,PC/Pani and PC are assembled into asymmetric supercapacitors,and PC/Pani exhibits good capacitance performance and long-term cycle stability.After cycling 3000 cycles at 5 A·g^-1,the assembled PC/Pani asymmetric supercapacitor retained 91%of the initial capacitance.Due to its low preparation cost and excellent electrochemical performance of the prepared composites,PC/Pani has great potential in practical electrodes for supercapacitors.?2?Preparation of N-doped carbon nanomaterials and their applications in supercapacitors.The porphyrin is used as a nitrogen source and potassium citrate is used as a carbon source to prepare a porous carbon nanomaterial by calcining melamine and potassium citrate into a mixed powder.The method is simple and the raw material is cheap and easy to obtain.The mass ratio of the nitrogen source to the carbon source and the optimum calcination temperature were explored in the experiment.It is found through research that when the mass ratio of potassium citrate and melamine is 2:1,the morphology of the prepared nitrogen-doped carbon nanomaterial is tubular structure different from other ratios.The prepared carbon material has a high nitrogen content of 14.31%.When the calcination temperature is 800?,the capacitance of the nitrogen-doped carbon nanomaterial can reach 264.6 F·g^-1 when the current density is 1 A·g^-1.?3?Preparation of porous carbon nanomaterials from latex sponge trim and their use in supercapacitors.The latex sponge trim was pulverized with a pulverizer then it was uniformly mixed with different mass of KOH solution,followed by drying in an oil bath at 130 C.The dried latex sponge scrap is calcined at a high temperature to prepare S,O co-doped porous carbon nanomaterial.The S,O co-doped porous carbon nanomaterial has a uniform porous structure.The synthesized carbon material is excellent in electrochemical performance.Moreover,the material has a high specific surface area of 1854.3 m²·g^-1.When the current density is 1 A·g^-1,its capacitance is 430 F·g^-1.After 5000 cycles at 5 A·g^-1 it retains 74%of the initial capacitance.