Aqueous organic redox-targeting flow battery based on Nernstian-potential-driven anodic redox-targeting reactions

Abstract

Aqueous organic flow batteries (AOFBs) hold a great promise for large-scale energy storage applications because of high theoretical specific capacity, the use of only earth-abundant elements, ease of large-scale manufacturing...

A high-capacity 1,2:3,4-dibenzophenazine anode integrated into carbon felt for an aqueous organic flow battery in alkaline media

“…However, since the electrical energy storage in a RTFB cell involves two consecutive steps – an electrochemical reaction that takes place on the surface of the electrode and a redox-targeting chemical reaction that take places in the tank – the utilization of solid-state active materials would be limited by the sluggish redox-targeting reaction kinetics at high current densities, resulting in a poor accessible capacity and a low lifetime. 7,27,28…”

“…1,2 Thus, largescale electrical energy storage devices are urgently needed to buffer the impact of intermittent renewable electricity generation and improve the power quality of the grid. 3 As one of the most promising battery storage technologies for an electrical grid, flow batteries (FBs) that can store large amounts of electrical energy in redox-active substances dissolved in electrolytes have the advantages of strong scalability, modular design, independent control of energy and power and so on, [4][5][6][7] attracting a great deal of attention from academia and industry.…”

“…Additionally, the zinc anode often suffers from poor cyclability 16,17 while the capacity of the organic anode usually does not match that of the liquid catholyte due to the low mass loading of redox-active organic substances at the anodic substrate. 18,19 Redox-targeting flow batteries (RTFBs) previously reported by the Wang group 15,[22][23][24] and other researchers, 7,25,26 which store and release electrical energy via thermodynamically allowed targeting chemical reactions between redox mediators dissolved in liquid electrolytes and solid-state electrode materials, can increase the energy density while maintaining the decoupling of energy from power. However, since the electrical energy storage in a RTFB cell involves two consecutive stepsan electrochemical reaction that takes place on the surface of the electrode and a redox-targeting chemical reaction that take places in the tankthe utilization of solid-state active materials would be limited by the sluggish redox-targeting reaction kinetics at high current densities, resulting in a poor accessible capacity and a low lifetime.…”

“…However, since the electrical energy storage in a RTFB cell involves two consecutive stepsan electrochemical reaction that takes place on the surface of the electrode and a redox-targeting chemical reaction that take places in the tankthe utilization of solid-state active materials would be limited by the sluggish redox-targeting reaction kinetics at high current densities, resulting in a poor accessible capacity and a low lifetime. 7,27,28 In this work, we have developed a novel organic anode with a high mass loading of active materials by integrating a waterinsoluble phenazine derivative (1,2:3,4-dibenzophenazine, DBPZ) into a carbon felt substrate via a deep eutectic solvent (DES)-assisted preparation approach. The AHFB employing this high-loading DBPZ anode achieves a high current density, a large areal capacity and remarkable cycling stability.…”

Thianthrene polymers as 4 V-class organic mediators for redox targeting reaction with LiMn2O4 in flow batteries

“…There are variations of the mediators, represented by organic redox-active molecules, metallocene, ferricyanide, iodine, and polysulfides 15,16 . As high-density materials, inorganic metal oxides have mainly been examined, in addition to solid-state or gel-like organic compounds [17][18][19] . Initially, a prototype system was demonstrated using metallocene mediators and LiFePO 4 and TiO 2 as metal oxides, yielding a capacity of over 240 Ah/L per tank 13 .…”