Chemical capacitance of nanoporous-nanocrystalline TiO₂in a room temperature ionic liquid

Abstract

The electrochemical behaviour of nanoporous TiO(2) in a room temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (EMITFSI), was investigated by cyclic voltammetry (CV) and impedance spectroscopy. Exponentially rising currents in voltammetry were attributed to the charging/discharging of electrons in the TiO(2) film and a charge transfer mechanism. The main features of the voltammetry and impedance followed the same trends in the ionic liquid as in other organic solvents and also in aqueous electrolytes. In the presence of lithium ions, the onset potential of the charge accumulation increased due to the change of the initial position of the TiO(2) conduction band. The results show that substitution of organic solvents contained in solar cells, supercapacitors or other electrochemical devices is in general feasible, though requires some adjustment in the electrolyte composition for optimal performance.

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“…The IPCE action spectrum for suggesting that electron transport occurs mainly through the TiO 2 nanoparticles rather than through QDs. 21 Furthermore, the transport resistance (R tr ) for TiO 2 is very similar in the dark and under illumination (Figure 4a). This is an expected result, since the conductivity of the TiO Finally, the recombination resistance, R rec is governing the photoelectrochemical behavior of the heterostructure, since the total resistance obtained by derivation of the j-V curve, also including series resistances, practically mimics the R rec values obtained by impedance spectroscopy both in the dark (Figure 4c) and under illumination (Figure 4d).…”

“…[20][21][22] . Labeling experiments of the evolved gas at the Pt counterelectrode was collected in an inverted burette and analyzed.…”

Correlation between Photovoltaic Performance and Impedance Spectroscopy of Dye-Sensitized Solar Cells Based on Ionic Liquids

“…From the electrochemical point of view, ionic liquids have excellent properties: they exhibit high-ionic conductivity and wide potential windows. [14][15][16][17][18][19][20] Furthermore, they are nonvolatile, nonflammable, and have high thermal stability, making them especially suitable for long term outside DSC applications avoiding problems such as leakage and evaporation of the organic solvent that are notorious for conventional solventcontaining electrolytes.…”

Enhancement of the capacitance in TiO2 nanotubes through controlled introduction of oxygen vacancies

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