Carbon anodes have been widely utilized for the fabrication of high-performance asymmetric supercapacitors. However, they generally suffer from unsatisfactory energy density due to low specific capacitance arising from inferior conductivity and insufficient ionic diffusion rate. Here a surface modification method is conducted after the annealing of ZIF-67 precursor to produce hydrophilic, porous and heteroatom-doped carbon foam. On top of enhanced area capacitance, widened voltage window of −1.3–0 V (vs saturated calomel electrode) can be achieved through electrochemical reduction to suppress the hydrogen evolution reaction. The optimized reduced porous carbon foam on carbon cloth exhibits a maximum area capacitance of 1049 mF/cm2 at an applied current density of 12 mA/cm2 with excellent capacitance retention of 98.4% after 6000 charge-discharge cycles at 15 mA/cm2. By well pairing with hierarchical MnO2/CC cathode, a 2.3 V asymmetric supercapacitor in neutral aqueous Na2SO4 electrolyte is assembled, which delivers an exceptional energy density of up to 10.07 mWh/cm3. The procedure in this paper for carbonaceous material to simultaneously achieve considerable capacitance and enlarged voltage window can open up a wider prospect toward design of anodes for high-performance aqueous supercapacitor.

Hierarchical porous carbon foam supported on carbon cloth as high-performance anodes for aqueous supercapacitors

Tofik Ahmed Shifa .
Writing – Review & Editing
;
2019-01-01

Abstract

Carbon anodes have been widely utilized for the fabrication of high-performance asymmetric supercapacitors. However, they generally suffer from unsatisfactory energy density due to low specific capacitance arising from inferior conductivity and insufficient ionic diffusion rate. Here a surface modification method is conducted after the annealing of ZIF-67 precursor to produce hydrophilic, porous and heteroatom-doped carbon foam. On top of enhanced area capacitance, widened voltage window of −1.3–0 V (vs saturated calomel electrode) can be achieved through electrochemical reduction to suppress the hydrogen evolution reaction. The optimized reduced porous carbon foam on carbon cloth exhibits a maximum area capacitance of 1049 mF/cm2 at an applied current density of 12 mA/cm2 with excellent capacitance retention of 98.4% after 6000 charge-discharge cycles at 15 mA/cm2. By well pairing with hierarchical MnO2/CC cathode, a 2.3 V asymmetric supercapacitor in neutral aqueous Na2SO4 electrolyte is assembled, which delivers an exceptional energy density of up to 10.07 mWh/cm3. The procedure in this paper for carbonaceous material to simultaneously achieve considerable capacitance and enlarged voltage window can open up a wider prospect toward design of anodes for high-performance aqueous supercapacitor.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/3742836
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