Study On The Preparation And Electrochemical Properties Of Sucrose-based Carbon Materials

Given the rapid economic development world-wide,the consumption of fossil energy is becoming increasing serious and the environmental pollution problems have been unable to solve.These problems greatly limit the economic development and improvement of the population's quality of life.Therefore,the development of new alternative energy sources is crucial.Supercapacitors have been paid increasing attention due to their high power and high energy density,fast charge and discharge,long life,green renewable and so on.In the field of supercapacitor electrode materials research,carbon materials are extensively used in the preparation of high-performance electrode materials due to their high specific surface area,good electrical conductivity,simple preparation process,control of microstructure,various forms,etc..The aim of this paper is to prepare high performance activated carbon electrode materials by high temperature carbonization activation using cheap renewable biomass carbon sources as precursors.The precursors were modified by different chemical activation reagents,carbonization temperature,time,and impregnation ratio,and the pore structure of the activated carbon was changed to improve the electrochemical performance of the activated carbon.By comparing the effect of the specific surface area,pore volume,and pore structure on the electrochemical properties of the electrode material,the preparation process of the new activated carbon electrode material was explored.Herein,sucrose was used as a precursor of carbonaceous materials,and activated carbon was prepared through various synthetic methods.The performance of the activated carbon was assessed.Carbon is a typical material of double electric layer electrode materials.Take sucrose as raw material,the researches of using chemical activation and in situ growth method to preparate high performance carbon electrode materials were rarely.In this paper,the carbon electrode materials were prepared by one-step activation,two-step activation and in-situ growth method.The materials were characterized by a variety of test methods,the effects of different activation conditions on the microstructure and electrochemical properties of the electrode materials were investigated.The main research results are as follows:1.Using sucrose as a raw material,a high performance activated carbon was prepared through a one-step H3PO4 chemical activation method.Through a series of microscopic characterization and performance tests,the effects of the activation conditions on the morphology,microstructure,and electrochemical performance of activated carbons were thoroughly investigated.The optimum conditions were as follows: an activation temperature of 500 ?,activation time of 1 h,and a H3PO4:sucrose ratio of 5:1(g/g).The resulting activated carbons showed a high specific surface area of 1188 m2 g-1 and a large pore volume of 0.89 cm3 g-1.The maximum specific capacitance was 154.9 F g-1.2.Using the high performance activated carbon prepared through a one-step H3PO4 chemical activation method as the raw material,a KOH high temperature chemical activation method was used to modify the surface of activated carbon.Compared to the one-step activation,the electrochemical properties were further improved.Through a series of microscopic characterization and performance tests,the effects of activation conditions on the morphology,microstructure,and electrochemical performance of activated carbons were thoroughly investigated.The optimum conditions were as follows: an activation temperature of 800 ?,activation time of 1 h,and a KOH:raw material ratio of 6:1(g/g).The maximum specific surface area and pore volume were 3020 m2 g-1 and 2.38 cm3 g-1,respectively.The maximum specific capacitance was 240.8 F g-1.3.Using sucrose as the raw material,a high temperature and pressure hydrothermal carbonization method was used to prepare spherical hydrothermal carbon directly grown on the surface of nickel foam,and a high performance electrode material without the use of an adhesive was prepared.The lack of an adhesive greatly promotes the rapid transfer of electrons and ions within the electrode,reducing the contact resistance between the active material and the metal current collector.The as-prepared electrode materials were characterized by scanning electron microscopy,powder X-ray diffraction,cyclic voltammetry,and galvanostatic charge/discharge techniques.The effects of different hydrothermal temperatures,hydrothermal time,and sucrose amount on the morphology,microstructure,and electrochemical properties of the electrode materials were studied.The optimum conditions were as follows: a hydrothermal temperature of 180 ?,hydrothermal time of 16 h,and sucrose addition of 7.5 g.The maximum specific capacitance was 296 F g-1.In summary,the preparation process and electrochemical performance of sucrose-based electrode materials have been studied in detail.The results show that the preparation technology of sucrose-based activated carbon is simple,the structure is controllable and the capacitance is excellent.Therefore,there materials can be used as supercapacitor electrodes in energy storage.