Self-doped TiO2 nanotube array photoanode for microfluidic all-vanadium photoelectrochemical flow battery

In this work, a self-doped TiO2 nanotube array (SD-TNA) photoanode was developed through a facile method for a microfluidic all-vanadium photoelectrochemical flow battery (mu VPFB) to achieve better solar energy storage performance. The TEM, XPS and XRD results confirmed successful self-doping, for which the light absorption range of the developed photoanode was extended to visible light. Meanwhile, one-dimensional nanotube structure promoted electron transport to enhance the separation of electrons and holes. The miniaturization of the flow battery reduced mass transfer resistance. Because of these merits, the mu VPFB with the SD-TNA photoanode yielded a relatively stable photocurrent density as high as 0.10 mA cm-2, which was much better than the conventional TNA photoanode, presenting about 100% improvement. The improvements in the photocurrent density and vanadium ion conversion rate could be achieved by upgrading both the intensity of light and concentration of vanadium ion.

Automated summary

A self-doped TiO2 nanotube array photoanode was developed for a microfluidic all-vanadium photoelectrochemical flow battery to enhance solar energy storage performance. The self-doping extended the light absorption range and the one-dimensional nanotube structure promoted electron transport and separation efficiency, while miniaturization reduced mass transfer resistance. Upgrading light intensity and vanadium ion concentration could further improve photocurrent density and vanadium ion conversion rate.