Preparation Of Porous Carbons From The By-products Of Coal Coking By Template Strategy And Their Electricity Storage Performance

Supercapacitor as one kind of important energy storage devices has been widely applied in hybrid electric vehicles,industrial power devices and consumer electronics by virtue of its high power density,short charging time and outstanding cycle stability.The electrochemical performance of supercapacitor mainly depends on the preporties of electrode materials.To date,activated carbons are the main electrode materials for commercial carbon-based supercapacitors.However,some long and tortuous pores in activated carbons are not accessible to the electrolyte ions,leading to poor rate capability and low capacitance.In this study,high-performance porous carbons for supercapacitors were obtained by employing template to regulate and control the porous structure and micro-morphology of carbon materials.The main results are as follows.Anthracene oil-based porous carbons?APCs?were prepared from magnesium carbonate basic pentahydrate,anthracene oil and KOH by facile one-step heating strategy.With the increase of template dosage from 6 g to 12 g,the morphology of APCs changes from sheets to hollow balls,the corresponding specific surface area decreases from 1574 m² g^-1 to 384 m² g^-1.As supercapacitor electrode,APC₆ exhibits a high specific capacitance of 306 F g^-1 at 0.05 A g^-1,good rate capacity of 230 F g^-1at 20 A g^-1 and superior cycle stability with 99.7%capacitance retention after 10000cycles.Coal tar-based porous carbons?CPCs?were prepared from magnesium carbonate basic pentahydrate and coal tar coupled with KOH activation.The as-made CPCs feature two-dimensional sheet-like structure with abundant micropores and a small number of mesopores.With the rise of heating temperature,the specific surface area of CPCs decreases from 2488 m² g^-1 to 2235 m² g^-1.As supercapacitor electrode,CPC₈₀₀ exhibits a high specific capacitance of 341 F g^-1 at 0.05 A g^-1,good rate capacity of 185 F g^-1 at 20 A g^-1 and superior cycle stability with 94.7%capacitance retention after 10000 cycles.Interconnected sheet-like porous carbons?ISPCs?were constructed from coal tar by using BMIMBF₄ ionic liquid as soft template coupled with chemical activation.The as-made three-dimensional ISPCs are composed of thin carbon nanosheets with abundant short pores,possessing a high specific surface area up to 1593 m² g^-1.Due to these synergistic structural characteristics,ISPCs as supercapacitor electrode exhibit an outstanding electrochemical performance with a high specific capacitance of 314 F g^-1 at 0.05 A g^-1,good rate capability of 195 F g^-1 at 100 A g^-1 and superior cycle stability with 97.1%capacitance retention after 10000 cycles.