Regulation Of Specific Surface Area And Pore Structure Of Coconut Shell Activated Carbon And Its Influence On The Performance Of Supercapacitors

Carbon double layer supercapacitors have higher power density and longer cycle stability.In recent years,more and more applications are in hybrid or pure electric vehicles,but the lower energy density limits its application.In this paper,Hainan special resources coconut,through the adjustment of single-factor synthesis of activated carbon,preparation of mesoporous high specific surface area of activated carbon,it has a high power density while maintaining high energy density.This can be widely applied to industrial equipment.In this paper,activated carbon with different specific surface area and pore size distribution was synthesized by adjusting the single factor of synthetic activated carbon.The best activated carbon AC-4 was prepared under conditions of single-factor activation temperature of 860?,activation time of 1 h,and ratio of alkali to carbon of 4:1,with a specific surface area of 3831 m2·g-1 and a pore volumeof 2.289 cm3 · g-1,which contains 42.3%mesopores.A higher specific surface area and mesopores respectively promoting capacity and providing a rapid transfer of ions channels.It was found that the mesopores playing an important role in enhancing the rate ability.This activated carbon can well meet the commercial requirements.The supercapacitors were assembled with the sample AC-4 have a high capacitance with 260 F · g-1 at a current density of 1 A · g-1,and the capacity still maintains about 90%after 10,000 cycles,excellent cycle performance;Coulomb efficiency remains almost 100%;100 A · g-1 still maintains 216.116 F · g-1,super high rate performance;Moreover,a high power density of 24.5 kW · kg-1 and energy density 13.35 Wh · kg-1 were achieved on the sample AC-4.Impedance test shows equivalent series resistance 0.3 ?,the lower impedance also shows that the material is conducive to ion shuttle.In order to increase the energy density of the parts,the ionic liquid with a wider voltage window was selected as the electrolyte.The specific capacitance reached 197 F · g-1 at 0.1 A · g-1,and remained at 44.23 Wh · kg-1 when the power density reached 78.46 kW · kg-1.These electrochemical tests show that coconut shell-based activated carbon prepared by this simple and convenient method has excellent capacitance properties and can be widely used in commercial applications.