Coal Tar Pitch-based Porous Carbon Prepared By Hard Template Method And Its Superelectric Properties

Supercapacitors(SCs)have been concerned by researchers due to long cycle life,high power density and fast charge/discharge rate.Porous carbon materials can be as a nice electrode material owing to its excellent conductivity,high specific surface area and interconnected pore structure.Coal tar pitch(CTP),as a main byproduct in coal processing process,which has a huge annual output and high carbon content.Therefore,it can be used as a carbon source to synthesize advanced porous carbon materials and apply them to supercapacitors.It is available to realize the resource and efficient utilization of coal tar pitch.In this paper,a series of pitch based porous carbon were synthesized by using coal tar pitch as carbon source,combined with hard template method and activation method,and its supercapacitance performance were studied.Firstly,hierarchical porous carbon(HPCs)was prepared by one-step carbonization activation method with coal tar pitch as carbon source,Ca O decomposed by Ca CO₃ as hard template and KOH as activator.It were studied that the effects of activator dosage,activation time and activation temperature on the morphology,structure and supercapacitor performance.The results show that the specific surface area will improve with the increase of activator dosage and activation temperature.The rate performance can improve with the increase of activation temperature,but the decrease of heteroatom content will lead to the decrease of pseudocapacitance and total specific capacitance.By comparing HPCs-0.5-600-1,HPCs-0.5-600-2 and HPCs-0.5-600-3,it can be seen that when the activation time is 2 hours,HPCs-0.5-600-2 has the largest specific surface area and higher specific capacitance and rate performance.Secondly,flower-like porous carbon sheet microspheres(PCSMs)were prepared by carbonization and activation with coal tar pitch as carbon source,flower-like basic zinc carbonate synthesized by hydrothermal method as template and KOH as activator.The effects of activation and zinc source concentration on the morphology,structure and supercapacitor performance of flower-like porous carbon sheet microspheres were studied.The results show that activation can also significantly improve the specific surface area and increase the spacing of carbon sheets,which is conducive to the penetration of electrolyte.Besides,the structure of the template is more compact with the increase of zinc source concentration,so the specific surface area gradually increase.In 6 M KOH electrolyte of three electrode system,the specific capacitance of PCSMs-0.2a at 1 A g^-1 and 50 A g^-1 is 313 F g^-1 and 256.5 F g^-1 respectively,and the capacitance retention is 81.9%.Finally,lamellated hierarchical porous carbon(LHPCs)were prepared via carbonization and activation using coal tar pitch as carbon source,lamellar basic magnesium carbonate as template and KOH as activator.It were studied that the effects of activation temperature and activator dosage on the morphology,structure and supercapacitor performance.The results display that the increase of activator dosage and activation temperature will lead the lamellated structure of the prepared porous carbon material more curved,and the increase of activator dosage gradually enhance the O content in the carbon material.When the activation temperature increases to 700?,the mesoporous in carbon material is the most abundant,and the surface area is 884.33m~2g^-1.The specific capacitance of LHPCs-1-700 electrode is 298 F g^-1 at 1 A g^-1 in 6 M KOH electrolyte in three-electrode system.