A new hydroxyanthraquinone derivative with a low and reversible capacity fading process as negolyte in alkaline aqueous redox flow batteries

High Energy Density Aqueous Flow Battery Utilizing Extremely Stable, Branching-Induced High-Solubility Anthraquinone near Neutral pH

“…Cells that used electrochemical capacity recovery are marked with a star. Data are from refs , , , − , , , − , , − , , , − .…”

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

“…However, PEG side chains induced high viscosity leading to high ASR values ranging from 1.8 to 2.2 Ω cm 2 when 1.5M PEGAQ was cycled in neutral AORFB. 2,6-dihydroxyanthraquinone [15], (((9,10-dioxo-9,10-dihydroanthracene-2,6diyl)bis(oxy))bis(propane-3,1-diyl))bis(phosphonic acid) (2,6-DPPEAQ) [16], alizarin-3methyliminodiacetic acid [17], 1,8-dihydroxyanthraquinone (1,8-DHAQ) [19], 1,2dihydroxyanthraquinone (1,2-DHAQ) [19], 3,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid (ARS) [13], anthraquinone-2,6-diethylphosphonic acid (AQDEP) [20], anthraquinone-2,6divinylphosphonic acid (AQDPV) [20], anthraquinone-2,6-propanoic acid (AQDP) [20], anthraquinone-2,6-diacrylic acid (AQDVC) [20], 3,3'-(anthraquinone-2,6-diyl)dibutyric acid (AQDB) [20], anthraquinone-2,6-crotonic acid (AQDBe) [20], 4,4′-(9,10-anthraquinonediyl)dibutanoic acid (DBAQ) [20], 3,3′-(9,10-anthraquinone-diyl)bis(3-methylbutanoic acid (DPivOHAQ) [20], 2,3-dihydroxyanthraquinone (2,3-DBAQ) [21], 1,8-dihydroxy-2,7dicarboxymethyl-9,10-anthraquinone (DCDHAQ) [22] in KOH solution at different pH.…”

“…However, the scientific and technical barriers to be lifted are better understood and preliminary analysis can be performed to prevent battery failure. For example, the solubility of the redox active species at different states of charge can be estimated to check that it will not precipitate during cycling, since the solubilities of reduced and oxidized forms can be very different [13,21]. The purity of commercially available compounds has also to be taken into account as it can influence their solubility [13].…”

“…Similar degradation products have been identified with other anthraquinones [22,25,49], although strong basic medium (pH 14) [20] and low charge-limiting SOC [22,25] seems to limit anthrone formation. Interestingly, it has been shown that anthrone can be reoxidized into anthraquinone by O 2 [48,50] or in cycling conditions involving a low discharge potential [21,51], allowing the possible introduction of a regeneration step during battery operation. Molecular engineering can also be a good mean to improve the stability of anthraquinone.…”

“…In the second case, the development of high selectivity membranes could be promoted but could likely increase the system cost as well. Promising alternatives have been reported in order to reduce the cost of the negolyte as the possibility to recover the capacity loss during operation by regenerating the electrolyte in the case of anthrone formation [21,51]. This method could be included in the control program and would not require any external intervention, thus limiting the OPEX increase.…”