Photoexcited-Charge Transfer and Energy–Storage Reaction of Photorechargeable TiO₂/Carbon Fibers Composite Electrodes

Abstract

A TiO2/carbon fibers (CFs) composite electrode is a solar device that converts photon energy to electrochemical energy and stores it in situ. The photoexcited-charge transfer and energy–storage reaction were studied. The results of photoelectrochemical measurements showed that the photoexcited electrons generated in TiO2 moved to CFs via ohmic contact. From a frequency response analysis of the electrochemical impedance, it was found that the electrical energy storage was realized by the formation of lithiated carbons at the CFs side. Since a large time constant was observed in the time variation of photo-emf, it was concluded that the low formation rate of lithiated carbons was one of the causes of small photocharged quantities.

Impacts of MnO2 Crystal Structures and Fe Doping in Those on Photoelectrochemical Charge–Discharge Properties of TiO2/MnO2 Composite Electrodes

“…Several types of photoelectrochemical energy storage devices have been recently reported. − Among them, a photoelectrochemical capacitor has the most favorable properties for portable device applications. Specifically, it can operate even at low photocharge voltages, because the adsorption reactions of Li + and Na + on electrodes requires much lower activation energy than their insertion reactions into the electrodes of batteries.…”

Charge transfer in photorechargeable composite films of TiO2and polyaniline

“…1(a). [14][15][16][17][18][19][20] Their storage part can be photocharged by carriers transferred from their photovoltaic part.…”

Regeneration of Nicotinamide Adenine Dinucleotide Phosphate by a Chlorophyll a-Coated TiO2 Film Electrode

“…This phenomenon can be applied to devices that combine energy conversion and storage. However, the photovoltage generated by photoelectric conversion is typically 1 V or less, which is not sufficient to promote the Li-insertion reaction because the charging voltage of Li-ion batteries is approximately 4 V. Thus, the Li + amount of photo-intercalation is significantly small. , Some researchers have recently suggested a photoelectrochemical capacitor as a new device that can overcome this problem. This device combines a capacitor material that can adsorb ions even with a low charging voltage with a photoelectric conversion material. − In their studies, TiO 2 electrodes were used for photoelectric conversion, whereas WO 3 or RuO 2 electrodes were used for energy storage.…”