Synthesis Of Porous Carbon Derived From Metal-organic Frameworks For High Performance Supercapacitors

As excellent energy storage-systems,supercapacitors possess many attractive features such as high power density,rapid charge-discharge process,long cycling life and low fabrication cost.Mostly,carbons are utilized as supercapacitors electrode materials,and the uniqueness of carbonaceous materials in supercapacitors field refer to their excellent characteristics like extensive surface area,ideal conducting property perfect electrochemical constancy for long duration and low fabrication cost.Usually,the structural properties of porous carbon play a very important role on its electrochemical performance,specially the surface area and microporosity which they are main key for interaction with the electrolyte ions and these features are significantly related to the selected carbon source.e.In recent time,metal organic frameworks(MOFs)constructing from combination of electropositive element(metal)and organic ligand,were widely employed as self-source/template of highly ordered porous carbon materials.Generally,MOFs have ideal advantages as porous carbon precursors such as highly ordered porous structures,large surface area,and well-uniform morphology.Also,the structural properties of carbon are usually improved by activation process to offer high electrochemical activity.In the current research work,different precursors of MOFs have been utilized to fabricate porous carbon materials by simple carbonization process combined with elimination of the metallic components by acid dissolution and activation.The synthesis conditions of porous carbon materials were further optimized that play considerable roles to enhance its electrochemical performance.Finally,the structural properties of porous carbon have been deeply studied by different characterization techniques and the electrochemical performance of the electrode was also studied via important techniques of cyclic voltammetry(CV),Galvanostatic charge-discharge test(GCD),electrochemical impedance spectroscopy(EIS).The main research contents are as followed:1,The present work proposes a novel activated porous carbon(APC1)which is derived from zinc-based metal organic frameworks as a source and template.The obtained APC1 has uniform unique spherical morphology with an average size of 3-5 ?m and a specific surface area up to 2,314.9 m2g-1.The activated porous carbon with superior mesoporous structure exhibits a high electrochemical performance in three-electrode system with 6 M KOH solution.It provides a high specific capacitance and power density of 325 F g-1 at a current density of 1 A g-1 and retains its specific capacitance with very slight decay rate of 1.21%after 150,000 cycles at an ultrahigh current density of 50 A g-1.Moreover,the APC1 symmetrical device has provided high energy densities of 12.15 and 9.48 Wh kg-1 when the power densities were 188 and 5,622 W kg-1 respectively.Hence,the present investigation demonstrates that the as-prepared activated porous carbon is a promising candidate as a low-cost and highly efficient electrode material for high-performance supercapacitors applications.2,An activated porous carbon(APC2)as supercapacitors electrode is synthesized from fluorine-containing metal-organic framework via a facile combined carbonization and KOH activation treatments.The electrochemical behavior of the APC2 electrode was further assessed by CV,EIS and GCD measurements using three-electrode setup in 6 M KOH electrolyte.This electrode delivers specific capacitances of 540.8 and 453.4 F g-1 at current densities of 1 and 100 A g-1,respectively with preeminent capacitance retentions of 97.7%after 150,000 cycles even at 50 A g-1,showing its outstanding capacitance,superb rate capability.Furthermore,for real applications the assembled symmetrical APC2 cell offers an energy density of 19 Wh kg-1 at power density of 182 W kg-1,indicating its large-scale application.This work proposes a potential route to synthesize highly efficient porous carbon for high performance energy storage devices.3,The current project introduces a highly activated porous carbon(APC3)derived from magnesium-based metal organic frameworks as effective precursor.The fabricated APC3 possesses an ordered spherical shape with an average size of 1-6 ?m as well as specific surface area of 2,175 m2g-1.The APC3 with adjusted mesoporous structure displays an excellent electrochemical efficiency using three-electrode configuration with 6 M KOH electrolyte.The APC3 electrode has offered specific capacitance of 362.5 F g-1 at a current density of 1 A g-1.Additionally,the APC3 electrode remains 94.2%of the initial specific capacitance after 150,000 cycles at high-load current density of 50 A g-1.Furthermore,the APC3 symmetrical cell has provided good energy densities of 7.99Wh kg-1 when the power density was 188 W kg-1.Accordingly,the present study illustrated that,the as-fabricated APC3is a promising applicant as highly effective electrode material for high-performance supercapacitors applications.4,The activated porous carbon(APC4)as electrode active material was obtained from the precursor of magnesium fluorinated metal-organic frameworks.The resulted APC4 material showed an adjusted mesoporous structure with huge surface area of 3,246.9 m2 g-1.The electrochemical properties of the assembled APC4 electrode were further studied through three-electrode configuration in 6 M KOH electrolyte.The fabricated electrode has exhibited high specific capacitance of 368 F g-1 at a current density of 1 A g-1 with superior capacitance retentions of 96.25%after 150,000 cycles at 50 A g-1,showing its highly electrochemical performance.Thereafter,for practical supercapacitors applications the designed APC4 symmetrical device delivered 8.67 Wh kg-1 at a power density of 187.5 W kg-1 denoting the good performance of APC4 in large-scale application.Regarding these observations,the APC4 can be considered as an excellent candidate for high performance energy storage systems.