Single and multi-frequency impedance characterization of symmetric activated carbon single capacitor cells

Abstract

<p class="PaperAbstractTitle"><span lang="EN-US">Electrochemical impedance spectroscopy (EIS) technique is used for characterization of single cell symmetric capacitors having different mass loadings of activated carbon (AC). Relevant values of charge storage capacitance (C<sub>T</sub>) and internal resistance (ESR) were evaluated by the single frequency and multi-frequency analyses of measured impedance spectra. Curve fittings were based on the non-ideal R-C model that takes into account the parasitic inductance, contributions from electrode materials/contacts and the effects of AC porosity. Higher C<sub>T</sub> and lower ESR values were obtained not only for the cell with higher mass of AC, but also using the single vs. multi-frequency approach. Lower CT and higher values of ESR that are generally obtained using the multi-frequency method and curve fittings should be related to the not ideal capacitive response of porous AC material and too high frequency chosen in applying the single frequency analysis.</span></p>

Palmyra palm flower biomass-derived activated porous carbon and its application as a supercapacitor electrode

“…Resistive components of all these impedances contribute to the internal electrode resistance value, which is generally determined by the electronic resistance of activated carbon particles, electronic resistance of the current collector to the active material and ionic resistance of electrolyte distributed within the pores. In a Nyquist plot, internal electrode resistance can be roughly defined by two impedance curve intercepts at Z′ axis, i.e., of the semicircle at high frequencies and the capacitive line at low frequencies [30,31].…”

Aktivni materijali koji se upotrebljavaju u superkondenzatorima

“…Electric Duble Layer Capacitor, EDLC) su superkondenzatori koji pohranjuju energiju tako da se formira elektrokemijski dvosloj na međufazi elektroda/elektrolit. 20 Tijekom postupka pražnjenja superkondenzatora dolazi do izbijanja akumuliranog Materijali koji se upotrebljavaju u elektrokemijskim dvoslojnim kondenzatorima su materijali na bazi ugljika kao što su aktivni ugljik, ugljikov aerogel, ugljikove nanocijevi, ugljikova nanovlakna te u novije vrijeme grafen i njegovi derivati. S ciljem postizanja velikih kapaciteta, razna istraživanja usmjerena su prema kontroli specifične površine i veličine pora ugljikovih materijala te povećanju električne provodnosti.…”