pH-Tuning a Solar Redox Flow Battery for Integrated Energy Conversion and Storage

Abstract

Experimental DetailsFlow Battery Measurements All flow battery electrochemical measurements were performed using a commercial Scribner redox flow cell with an active area of 5 cm 2 . The I3 -/Ibased catholyte was circulated using a PTFE diaphragm pump (Cole-Parmer) and PTFE tubing. The anthraquinone-2,7-disulfonic acid (AQDS, TCI) anolyte was circulated using a peristaltic pump (Cole-Parmer) and PTFE tubing (except at the pump head where flexible silicone tubing is required for pump operation). Both the anolyte and catholyte were circulated at a flow rate of 40 mL/min. An nitrogen atmosphere was maintained above the electrolytes to prevent oxidation of the AQDS. Nafion 212 membranes (DuPont) were used as the cation exchange membrane to separate the positive and negative electrolytes. The Nafion membranes were pretreated prior to use according to the following procedure: (1) stirred in a deionized (DI) water bath at ~ 80 o C for 30 mins. (2) stirred in a 3% H2O2 aqueous solution at ~ 80 o C for 45 mins. (3) washed with DI water (4) stirred in a 0.5 M H2SO4 solution at ~ 80 o C for 1 hour. (5) washed and stored in DI water until use. Carbon felt GFD 4.6 mm (SGL Carbon) was used for both electrodes. Flow battery cycling was conducted using a maccor model 4304 battery tester with a current density of 50 mA (10 mA/cm 2 ) unless otherwise stated. The pH of the flow battery electrolyte was

Integrated Photo‐Responsive Batteries for Solar Energy Harnessing: Recent Advances, Challenges, and Opportunities

“…In 2016, McCulloch et al. introduced a pH‐tunable solar redox flow battery with a two‐electrode setup, which contained a dye‐sensitized TiO 2 photoelectrode, a pH‐independent catholyte (I − /I 3 − ), and a pH‐dependent anolyte (AQDS/AQD 2− , Figure a) . During photocharging process, photoexcited electrons generated by dye‐sensitization were first injected into the TiO 2 and then transferred to the counter electrode through electric circuit to reduce the AQDS.…”

UV‐Triggered Optical Response and Oxygen Scavenging Ability of a Water‐Soluble Poly(N,N‐dimethylacrylamide‐co‐2‐vinylbenzylanthraquinone) Copolymer

“…For example, anthraquinone-2,7-disulphonic acid has been proposed to form the anolyte of solar rechargeable redox batteries. [33][34][35] On the other hand, the incorporation of dispersed or polymer-bound anthraquinone derivatives in polymeric packaging formulations has been proposed to scavenge unwanted oxygen. [36][37][38][39] Concerning energy-related applications, of special interest is the case of organic photovoltaic (OPV) devices.…”

“…The photoreduction/oxidation of AQ species have been also proposed for energy‐related applications. For example, anthraquinone‐2,7‐disulphonic acid has been proposed to form the anolyte of solar rechargeable redox batteries . On the other hand, the incorporation of dispersed or polymer‐bound anthraquinone derivatives in polymeric packaging formulations has been proposed to scavenge unwanted oxygen .…”

Photorechargeable High Voltage Redox Battery Enabled by Ta3N5 and GaN/Si Dual‐Photoelectrode

“…For instance, they have demonstrated that direct combination of dye‐sensitized solar cells (DSSC) with Li–O 2 batteries could effectively increase the round‐trip efficiencies of the system . Most recently, they achieved unassisted solar rechargeable flow batteries based on the AQDS (anthraquinone‐2,7‐disulphonic acid) anolyte and the iodide catholyte . Nevertheless, the discharge cell voltages of their systems are limited (<0.8 V).…”

“…The combined cell voltage (1.4 V) is slightly lower than the predicted 1.5 V from open circuit potential measurements. Possible reasons include the decrease of Ta 3 N 5 photovoltage caused by the positive shift of the conduction band edge of Ta 3 N 5 in pH 12 compared to pH 14 (59 mV per pH unit; Figure S7, Supporting Information) …”