Single-flow multiphase flow batteries: Experiments

Improved coulombic efficiency of single-flow, multiphase flow batteries via the use of strong-binding complexing agents

“…Besides, gravity and mixing conditions play a vital role in determining the electrolyte conductivity at a low flow rate and high polybromide volume fraction. 35 At high flow rates exceeding 250 mL min −1 , the measured electrolyte conductivity values by Ronen et al 35 at ψ = 5% with MEP are higher (∼95 mS cm −1 ) than that obtained here (77 mS cm −1 ) for ψ = 5% with MEP. This is likely due to differences in emulsion mixing conditions, since the latter authors used a conventional overhead mixer with a perforated bar for stirring the electrolyte, as compared to the use of a magnetic mixing bar used here (Fig.…”

“…3-MBPy exhibits slightly lower VE than MEP, likely because of the poorer conductivity of its viscous polybromide phase, which may have settled somewhat onto the cathode. 35 On the other hand, at ψ = 5%, 3-MBPy displays maximum CE and VE of 63% and 65% whereas MEP displays maximum of 43% CE and 64% VE respectively. Because of the high viscosity and low conductivity, increasing the polybromide volume fraction slightly reduces the CE and VE.…”

“…To further develop this concept, Ronen et al in a series of papers established analytical current-voltage relationships for batteries leveraging emulsive electrolytes and uncovered that the effect of gravity on the polybromide phase plays a crucial role particularly at low electrolyte flowrate. 8,35 A separate effort to develop emulsions as flow battery electrolytes was detailed by Peng et al 36 and Shen et al 37 utilizing microemulsions of immiscible organic and aqueous solvents. In the latter system, organic molecules (ferrocene) soluble only in the organic phase (toluene/tween 20/1-butanol) was used as the redox-active species.…”

Cathode materials for halide-based aqueous redox flow batteries: recent progress and future perspectives

“…There is research investigating bromine with different chemical agents in aqueous electrolytes for the complexation of RFB systems. 64 The bromine vapor pressure variation, the insoluble matter storage halogen, and the solid material form show the bromine high concentrations (13.6 M) stored in the fused salt, with the theoretical energy capacity rushing up to 730 Ah L −1 . 63,65 Recently, it was found that the hydrogen-bromine RFB (HBRFB) possesses higher specific power with a voltage efficiency of more than 90% and higher solubility in an aqueous solution, and is an interesting subject for research.…”

How anthraquinones can enable aqueous organic redox flow batteries to meet the needs of industrialization

“…This target cost comprises various parameters from engineering to raw materials costs [69]. The cost of a system is mostly driven by the electrolyte and the stack (especially the membrane, which represents ~20% of the stack cost [70]). Anthraquinone based electrolytes are usually described as low-cost materials, however, few thorough studies have been reported regarding that aspect.…”