Charge transfer in photorechargeable composite films of TiO₂and polyaniline

Abstract

A photorechargeable battery (PRB) is a photovoltaic device having an energy storage function in a single cell. The photoactive electrode of PRB is a bilayer film consisting of bare porous TiO 2 and a TiO 2 -polyaniline (PANi) mixture that work as a photovoltaic current generator and an electrochemical energy storage by ion dedoping, respectively. To study the charge transfer between TiO 2 and PANi, the photorechargeable quantum efficiency QE ([electron count on discharge]/[incident photon count on photocharge]) was measured by varying the thickness L S of the TiO 2 -PANi mixture. The quantum efficiency QE uv for UV photons had a maximum of >7% at L S > 7 µm. The time constant τ TP for the charge transfer was about 10 %1 s, which was longer ten times or more than the lifetime of excited electrons within TiO 2 . These facts reveal that the main rate-limiting factor in the photocharging process is the charge transfer between TiO 2 and PANi.

Light-induced Li extraction from LiMn2O4/TiO2 in a water-in-salt electrolyte for photo-rechargeable batteries

“…Recently, a new battery system that can be directly charged by light, called photorechargeable batteries (PRBs), has been proposed. [1][2][3][4][5][6][7][8][9][10] This type of battery offers more compact and simple designs than the combination of solar cells and conventional batteries. PRBs are therefore applicable to internet of things (IoT) devices, which are becoming increasingly common.…”

“…A difference from conventional batteries is that PRBs use photoactive materials. Photocatalysts, 1,2,5,6 dyes, 3,4 and cathode materials themselves 8–10 can be employed as them. It is energetically possible to charge electrode materials with the holes and excited electrons generated by illumination in the photoactive materials if the relationship between the energy levels is adequate (Fig.…”

“…Achieving charge separation using several substances is also a key to effective photocharging. Previous studies have reported various combinations of materials, for example, LiFePO 4 /N719-dye, 3 Cu 2 S/dye-sensitized TiO 2 , 4 polyaniline/TiO 2 , 5 V 2 O 5 /poly(3-hexylthiophene-2,5-diyl), 8,9 and VO 2 /ZnO. 10 It is, however, still challenging to use high-potential cathodes ( i.e.…”

Light energy storage in TiO2/MnO2 composite electrode for photoelectrochemical capacitor

“…Thus, solar power is unfavorable for current portable electronic devices with high power demands; however, it will be sufficiently useful for next-generation display devices like electronic paper, which have much lower power consumption. To increase storage efficiency and decrease device size, a single electrode should achieve both photoelectric conversion and energy storage, as some researchers have reported [1][2][3].…”

Optimizing LiMn1.5M0.5O4 cathode materials for aqueous photo-rechargeable batteries

“…In addition, PRBs are expected to be used for internet of things (IoT) devices, where photocharging would significantly improve the utility of such wireless devices. Various configurations of PRBs have been proposed so far, [4][5][6][7][8][9][10][11][12] and they roughly fall into two types: three- [7][8][9] and two-electrode [4][5][6][10][11][12] systems. The twoelectrode design is suitable for reducing the cost and size owing to the absence of an additional photoelectrode.…”