Carbogels: carbonized conducting polyaniline/poly(vinyl alcohol) aerogels derived from cryogels for electrochemical capacitors

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F19%3A00500356" target="_blank" >RIV/61389013:_____/19:00500356 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.rsc.org/en/content/articlelanding/2019/TA/C8TA09574D#!divAbstract" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2019/TA/C8TA09574D#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/C8TA09574D" target="_blank" >10.1039/C8TA09574D</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Carbogels: carbonized conducting polyaniline/poly(vinyl alcohol) aerogels derived from cryogels for electrochemical capacitors

Popis výsledku v původním jazyce

Polyaniline cryogels supported with poly(vinyl alcohol) represent soft conducting macroporous materials suitable for conversion to aerogels by freeze-drying and, subsequently, to nitrogen-containing carbogels by carbonization in an inert atmosphere at 500–600 °C. The process was followed by thermogravimetric analysis and Raman spectroscopy at the molecular level. The spectral features indicate a significant degree of structural disorder in the material due to the extensive nitrogen and oxygen incorporation into the carbon sp2 network, which is important for the improvement of capacitive performance. The macroporous morphology is preserved after carbonization but the specific surface area increased from 12 to 680 m2 g−1 after exposure to 500 °C in an inert atmosphere. The original conductivity of the cryogel swollen with an acid solution, 0.07 S cm−1, was reduced to 2 × 10−4 S cm−1 for the aerogel and again to 10−9 S cm−1 as the carbonization progressed. The impedance spectra display Maxwell–Wagner–Sillars relaxation typical of heterogeneous composite systems with the contribution of ionic conductivity. The decrease in conductivity is in agreement with the significant drop in the static dielectric constant observed by broad-band dielectric spectroscopy and decrease in the spin number determined by electron paramagnetic resonance spectroscopy. Switching in the capacitive response from that dominated by faradaic surface processes at lower treatment temperatures to that of double-layer charging at elevated temperatures is evidenced, while the correlation between surface spin density and specific capacitance is emphasized. The results can be used as guidance for the rational design of novel active materials for electrochemical capacitors.

Název v anglickém jazyce

Carbogels: carbonized conducting polyaniline/poly(vinyl alcohol) aerogels derived from cryogels for electrochemical capacitors

Popis výsledku anglicky

Polyaniline cryogels supported with poly(vinyl alcohol) represent soft conducting macroporous materials suitable for conversion to aerogels by freeze-drying and, subsequently, to nitrogen-containing carbogels by carbonization in an inert atmosphere at 500–600 °C. The process was followed by thermogravimetric analysis and Raman spectroscopy at the molecular level. The spectral features indicate a significant degree of structural disorder in the material due to the extensive nitrogen and oxygen incorporation into the carbon sp2 network, which is important for the improvement of capacitive performance. The macroporous morphology is preserved after carbonization but the specific surface area increased from 12 to 680 m2 g−1 after exposure to 500 °C in an inert atmosphere. The original conductivity of the cryogel swollen with an acid solution, 0.07 S cm−1, was reduced to 2 × 10−4 S cm−1 for the aerogel and again to 10−9 S cm−1 as the carbonization progressed. The impedance spectra display Maxwell–Wagner–Sillars relaxation typical of heterogeneous composite systems with the contribution of ionic conductivity. The decrease in conductivity is in agreement with the significant drop in the static dielectric constant observed by broad-band dielectric spectroscopy and decrease in the spin number determined by electron paramagnetic resonance spectroscopy. Switching in the capacitive response from that dominated by faradaic surface processes at lower treatment temperatures to that of double-layer charging at elevated temperatures is evidenced, while the correlation between surface spin density and specific capacitance is emphasized. The results can be used as guidance for the rational design of novel active materials for electrochemical capacitors.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of materials chemistry A

ISSN

2050-7488

e-ISSN

—

Svazek periodika

7

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

1785-1796

Kód UT WoS článku

000459724300041

EID výsledku v databázi Scopus

2-s2.0-85060450295