Increase of porosity by combining semi-carbonization and KOH activation of formaldehyde resins to prepare high surface area carbons for supercapacitor applications

Heimböckel, Ruben; Kraas, Sebastian; Hoffmann, Frank; Fröba, Michael

doi:10.1016/j.apsusc.2017.08.095

Cited by 54 publications

(16 citation statements)

References 72 publications

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“…[ 44,45 ] These results are typical and similar to those we found previously for structures formed when using a PEO‐ b ‐PCL copolymer as the template. [ 42 ] In addition, the capacitances of the electrode materials obtained at all activated carbon ratios were quite similar (Figure S4, Supporting Information), suggesting that the different mesoporous carbons did not possess different chemical structures and they did not display different electrochemical behavior. This also was supported by the similar EDLC as well as PC performance obtained at all investigated scan rates.…”

Section: Resultsmentioning

confidence: 93%

“…[ 41 ] All of the activated mesoporous carbons derived from the various PEO‐ b ‐PLA ratios provided similar EDLC curves within the investigated range, suggesting uniform carbon structures after activation at all of the ratios. [ 42,43 ] Furthermore, we observed evidence for a mild pseudocapacitor reaction at the edges of the curves, possibly due to functionalization with oxygen and nitrogen atoms during the high‐temperature activation process. [ 44,45 ] These results are typical and similar to those we found previously for structures formed when using a PEO‐ b ‐PCL copolymer as the template.…”

Section: Resultsmentioning

confidence: 97%

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Varying the Hydrogen Bonding Strength in Phenolic/PEO‐b‐PLA Blends Provides Mesoporous Carbons Having Large Accessible Pores Suitable for Energy Storage

Lee

Ahmed

et al. 2020

Macro Chemistry & Physics

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as efficient electron transfer media to improve the performance of electric double-layer capacitors (EDLCs). [9] Furthermore, the blending of a self-assembled block copolymer with the carbon source (e.g., phenolic resin) is becoming more widespread. This method has the advantage of providing well-ordered mesoporous structures that can be used efficiently in various applications. [10,11] Typically, a block copolymer that forms a self-assembled structure is mixed with a carbon source to obtain various dimensional carbon structures. The blending of a commercial Pluronic-type triblock copolymer, such as poly(ethylene oxide-b-propylene oxideb-ethylene oxide), as the template is the method used most widely to prepare mesoporous materials. [12][13][14][15][16][17][18][19] Because of limitations in molecular weight and composition, it can, however, be difficult to prepare mesoporous materials having pore sizes of greater than 10 nm when using Pluronic-type triblock copolymers. Block copolymers featuring long hydrophobic segments and high molecular weight-for instance, poly(ethylene oxideb-styrene) (PEO-b-PS) [20,21] and poly(ethylene oxide-b-methyl methacrylate) (PEO-b-PMMA) [22] -are promising candidates as templates to prepare large-pore-size mesoporous carbons. For example, Zhao et al. prepared mesoporous carbons with long-range order, large surface areas (>1500 m 2 g −1 ), and large pores (≈23 nm) when using PEO 125 -b-PS 230 as the template as displayed in Scheme S1a-c in the Supporting Information. [21] With PEO 125 -b-PMMA 114 as the template, they obtained mesoporous carbons having large surface areas (>1500 m 2 g −1 ) and pores (≈10 nm) [22] when applying resol as the carbon source. Mesoporous carbons with smaller pores but thicker walls were obtained when using PEO-b-PMMA as the template, rather than PEO-b-PS, because the phenolic OH units could interact strongly with the PEO segment (interassociation equilibrium constant (K A ) = 286) [23] and weakly with the PMMA CO units (K A = 20) [24,25] through hydrogen bonding, but not with the hydrophobic PS segment. Indeed, the PS block segment would undergo complete microphase In this study, mesoporous carbons are prepared by using a resol-type phenolic resin as the carbon source and poly(ethylene oxide-b-lactic acid) (PEO-b-PLA) copolymer as the template, with a process of thermal curing, calcination, carbonization, and activation. The structures of these mesoporous carbons are strongly influenced by the self-assembled structures formed from phenolic/PEO-b-PLA blends, varying from double-gyroid, to cylinder, and finally to spherical micelle structures upon increasing the phenolic concentrations. The large pores (>20 nm) and high surface areas (>1000 m 2 g −1 ) of these activated mesoporous carbons arise because the phenolic resin interacts only with the PEO segment (i.e., not with the PLA segment) through hydrogen bonding; thus, the relative wall thickness of the phenolic matrix decreases after template removal (thereby increasing the pore size), similar to the beha...

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 97%

Varying the Hydrogen Bonding Strength in Phenolic/PEO‐b‐PLA Blends Provides Mesoporous Carbons Having Large Accessible Pores Suitable for Energy Storage

Lee

Ahmed

et al. 2020

Macro Chemistry & Physics

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“…The typical synthesis of high surface area carbons (HSACs) was already presented in ref. 20. In short, 2.2 g phenol (ABCR) were dissolved in 30 g ethanol.…”

Section: Materials Synthesismentioning

confidence: 99%

“…8,19 We recently demonstrated the importance of the pre-carbonization temperature used prior to the chemical activation with KOH. 20 A lower pre-carbonization temperature leads to an enlargement of pores, resulting in carbon materials with larger pore volume and specific surface area. Therefore, it is possible to tailor the pore size, total pore volume, micropore volume and surface area by varying the pre-carbonization temperature and the amount of activation agent.…”

Section: Introductionmentioning

confidence: 99%

Insights into the influence of the pore size and surface area of activated carbons on the energy storage of electric double layer capacitors with a new potentially universally applicable capacitor model

Heimböckel

Hoffmann

Fröba

2019

Phys. Chem. Chem. Phys.

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132

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“…Supercapacitors have attracted much attention due to their fast charge/discharge capability, long cycle life, and high power density . As the new type of energy device, supercapacitors have kinds of electrode materials such as carbon materials, conducting polymers, metallic oxide, and so on .…”

Section: Introductionmentioning

confidence: 99%

Carbonized thiourea formaldehyde resin blending polypyrrole hollow spheres composites with improved supercapacitor performances as electrodes

Jiang

Niu

et al. 2019

J of Applied Polymer Sci

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Thiourea formaldehyde resin has been condensation‐polymerized in the polypyrrole hollow spheres suspension to obtain TF/PPy. Then, TF/PPy has been carbonized at 750 °C to acquire CTF/PPy composites. Scanning electron microscope and transmission electron microscope images were used to observe the morphology of the samples, TGA, XRD, Raman, XPS, and BET were used to analyze the structure of the materials. The results show PPy was blended with the TF resin, and the obtained CTF/PPy exhibited improved supercapacitive performances compared with CTF. The specific capacitance of CTF/PPy is 226.8 F g−1 at the current density of 1 A g−1 according to GCD curves, much higher than that of CTF. More interestingly, the cycling retention of CTF/PPy electrode at the current density of 10 A g−1 is up to 120.2% after 10 000 cycles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47816.

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Increase of porosity by combining semi-carbonization and KOH activation of formaldehyde resins to prepare high surface area carbons for supercapacitor applications

Cited by 54 publications

References 72 publications

Varying the Hydrogen Bonding Strength in Phenolic/PEO‐b‐PLA Blends Provides Mesoporous Carbons Having Large Accessible Pores Suitable for Energy Storage

Varying the Hydrogen Bonding Strength in Phenolic/PEO‐b‐PLA Blends Provides Mesoporous Carbons Having Large Accessible Pores Suitable for Energy Storage

Insights into the influence of the pore size and surface area of activated carbons on the energy storage of electric double layer capacitors with a new potentially universally applicable capacitor model

Carbonized thiourea formaldehyde resin blending polypyrrole hollow spheres composites with improved supercapacitor performances as electrodes

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