Abstract:Advancement
in the application of biomass-derived carbon is viewed
as one of the most important drivers of sustainable and renewable
technologies for energy storage. High-performance biochar with a well-defined
structure is extremely attractive as a supercapacitor electrode material.
Herein, carbon with an ultrahigh capacitance of 682 F/g at 0.2 A/g
for biochar materials and remarkable cycling stability was synthesized
from Chinese parasol fluff (CPF). Three-dimensional interconnected
hierarchical porous carbo… Show more
“…The Ragone plots of the BLHPC-Zn/K// BLHPC-Zn/K symmetric supercapacitor are presented in Figure 6 c. Benefiting from the high potential window, the maximum energy density can reach to 51.3 W h kg −1 at a power density of 250 W kg −1 ; even at high power density (15 kW kg −1 ), the symmetric supercapacitor can provide an energy density of 34 W h kg −1 . Such superior energy density and power density has an advantage over most of previously reported biomass-carbon-based symmetric supercapacitors ( Table S2 ) [ 16 , 47 , 48 , 49 , 50 , 51 ]. Moreover, the symmetric supercapacitor delivers remarkable cycling stability with capacitance retention of 94.6% after 10,000 cycles at a current density of 4 A g −1 , suggesting an excellent practical value ( Figure 6 f).…”
High specific surface area, reasonable pore structure and heteroatom doping are beneficial to enhance charge storage, which all depend on the selection of precursors, activators and reasonable preparation methods. Here, B, O and N codoped biomass-derived hierarchical porous carbon was synthesized by using KCl/ZnCl2 as a combined activator and porogen and H3BO3 as both boron source and porogen. Moreover, the cheap, environmentally friendly and heteroatom-rich laver was used as a precursor, and impregnation and freeze-drying methods were used to make the biological cells of laver have sufficient contact with the activator so that the layer was deeply activated. The as-prepared carbon materials exhibit high surface area (1514.3 m2 g−1), three-dimensional (3D) interconnected hierarchical porous structure and abundant heteroatom doping. The synergistic effects of these properties promote the obtained carbon materials with excellent specific capacitance (382.5 F g−1 at 1 A g−1). The symmetric supercapacitor exhibits a maximum energy density of 29.2 W h kg−1 at a power density of 250 W kg−1 in 1 M Na2SO4, and the maximum energy density can reach to 51.3 W h kg−1 at a power density of 250 W kg−1 in 1 M BMIMBF4/AN. Moreover, the as-prepared carbon materials as anode for lithium-ion batteries possess high reversible capacity of 1497 mA h g−1 at 1 A g−1 and outstanding cycling stability (no decay after 2000 cycles).
“…The Ragone plots of the BLHPC-Zn/K// BLHPC-Zn/K symmetric supercapacitor are presented in Figure 6 c. Benefiting from the high potential window, the maximum energy density can reach to 51.3 W h kg −1 at a power density of 250 W kg −1 ; even at high power density (15 kW kg −1 ), the symmetric supercapacitor can provide an energy density of 34 W h kg −1 . Such superior energy density and power density has an advantage over most of previously reported biomass-carbon-based symmetric supercapacitors ( Table S2 ) [ 16 , 47 , 48 , 49 , 50 , 51 ]. Moreover, the symmetric supercapacitor delivers remarkable cycling stability with capacitance retention of 94.6% after 10,000 cycles at a current density of 4 A g −1 , suggesting an excellent practical value ( Figure 6 f).…”
High specific surface area, reasonable pore structure and heteroatom doping are beneficial to enhance charge storage, which all depend on the selection of precursors, activators and reasonable preparation methods. Here, B, O and N codoped biomass-derived hierarchical porous carbon was synthesized by using KCl/ZnCl2 as a combined activator and porogen and H3BO3 as both boron source and porogen. Moreover, the cheap, environmentally friendly and heteroatom-rich laver was used as a precursor, and impregnation and freeze-drying methods were used to make the biological cells of laver have sufficient contact with the activator so that the layer was deeply activated. The as-prepared carbon materials exhibit high surface area (1514.3 m2 g−1), three-dimensional (3D) interconnected hierarchical porous structure and abundant heteroatom doping. The synergistic effects of these properties promote the obtained carbon materials with excellent specific capacitance (382.5 F g−1 at 1 A g−1). The symmetric supercapacitor exhibits a maximum energy density of 29.2 W h kg−1 at a power density of 250 W kg−1 in 1 M Na2SO4, and the maximum energy density can reach to 51.3 W h kg−1 at a power density of 250 W kg−1 in 1 M BMIMBF4/AN. Moreover, the as-prepared carbon materials as anode for lithium-ion batteries possess high reversible capacity of 1497 mA h g−1 at 1 A g−1 and outstanding cycling stability (no decay after 2000 cycles).
“…Owing to the good rate capability, when the current density increases to 20 A g −1 , the energy density maintains 25 Wh kg −1 at an ultrahigh power density of 15 kW kg −1 , which is still superior to that in the aqueous electrolyte of 6 M KOH (12 Wh kg −1 ). It is noted that commercial supercapacitor usually has a relatively low energy density (< 5Wh kg −1 ), which is usually lower than 10% of the NHPC-5 based device 71 , 72 . Figure 7 Supercapacitor performance of NHPC-5 in an organic electrolyte: ( a ) CV curves, ( b ) GCD curves, ( c ) specific capacitances calculated from the GCD curves; ( d ) Ragone plots of the power density vs energy density; ( e ) electrochemical durability was tested through 10,000 cycles at a high charge–discharge current density of 10 A g −1 ; ( f ) Nyquist plots in comparison of before and after long-cycle test.…”
Carbon-based supercapacitors have aroused ever-increasing attention in the energy storage field due to high conductivity, chemical stability, and large surface area of the investigated carbon active materials. Herein, eucalyptus-derived nitrogen/oxygen doped hierarchical porous carbons (NHPCs) are prepared by the synergistic action of the ZnCl
2
activation and the NH
4
Cl blowing. They feature superiorities such as high specific surface area, rational porosity, and sufficient N/O doping. These excellent physicochemical characteristics endow them excellent electrochemical performances in supercapacitors: 359 F g
−1
at 0.5 A g
−1
in a three-electrode system and 234 F g
−1
at 0.5 A g
−1
in a two-electrode system, and a high energy density of 48 Wh kg
−1
at a power density of 750 W kg
−1
accompanied by high durability of 92% capacitance retention through 10,000 cycles test at a high current density of 10 A g
−1
in an organic electrolyte. This low-cost and facile strategy provides a novel route to transform biomass into high value-added electrode materials in energy storage fields.
“…Co 2+ served as the ion additive for carbon graphitization such that the as-prepared porous material presented high SSA of 1449 m 2 g À1 and rich heteroatom content. 188 Likewise, acetic acid mediated synthesis of chitosan-based hierarchical porous carbon showed unique honeycomb-like structure and high surface area of 3532 m 2 g À1 (Fig. 10a).…”
In recent times, increasing environmental pollution alongside depletion of fossil fuel reserves has led to a rejuvenated interest in utilizing biomass and waste materials. Advanced porous carbons derived from such...
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