Preparation And Electrochemical Properties Of Biomass-based Porous Carbon

As a renewable green energy,the full utilization and development of biomass energy can not only achieve sustainable economic development,but also reduce the consumption of fossil energy and the deterioration of the global environment.Biomass porous carbon has the advantages of low price,environmental friendliness,large specific surface area,strong conductivity,good chemical stability,etc.As an excellent adsorbent,it can remove mold and pigment from food,regulate the gas concentration in packaging.It is also an ideal electrode material for supercapacitors,which can be widely used in energy storage,transportation,power,communication and other fields.However,there are few reports on algae biomass-based porous carbon.In this paper,biomass Laminaria japonica was used as carbon source to prepare heteroatomic self-doped porous carbon materials with different different morphologies and properties by hydrothermal carbonization and direct carbonization followed by activation.The porous carbons obtained by hydrothermal carbonization method show spherical morphology,and the amount of sulfuric acid added to the catalyst has a great impact on the structure and performance of the carbon microspheres.The sample CMS-15 has the largest specific surface area and total pore volume,which are 522.85 m2/g and 0.31 cm3/g,respectively.Besides,the addition of sulfuric acid increases the content of sulfur atoms in carbon microspheres but decreases the content of oxygen atoms.The carbon microspheres exhibit poor electrochemical performance due to its small specific surface area,total pore volume and large internal resistance.The activated carbons prepared by direct carbonization and KOH activation display a massive sponge structure with larger specific surface structure,more developed pore structure and better electrochemical performance in comparison.The PC-800 shows the largest specific surface area and total pore volume,which are 2088.31 m2/g and 1.38 cm3/g,respectively.The results of the study indicate that the product PC-700 has the best electrochemical performance:the specific capacitance of PC-700 can reach to 192 F/g at a current density of 0.1 A/g.When the current density increases to 10 A/g,the specific capacitance of PC-700 decays to 120 F/g and its capacitance retention rate is 62.5%,indicating a good rate performance.Furthermore,the coulombic efficiency and capacitance retention rate of PC-700 can up to about 99%after 10000 cycles of charge and discharge at 1A/g,indicating excellent cycle stability.Therefore,the laminaria japonica-based porous carbon prepared in this paper has great application potential in the field of adsorption and energy storage.