On the Mechanism of the Cathodic Reduction of Anthraquinone to Anthrone

Beck, F.; Heydecke, Gabriele

doi:10.1002/bbpc.19870910109

Cited by 34 publications

(10 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These observations strongly implicate anthrone formation and subsequent dimerization as the primary source of capacity loss. Anthrone and dianthrone species have also been reported to be products of the chemical reduction of anthraquinones and of the electrochemical reduction of anthraquinones in acidic aqueous solutions. ,− …”

Section: Resultsmentioning

confidence: 99%

“…Beck and Heydecke observed anthrone formation during electrochemical reduction of unsubstituted anthraquinone under highly acidic conditions and proposed homogeneous disproportionation as the mechanism by which this transformation occurs. 44 Two observations suggest that DHAHQ in alkaline solution undergoes disproportionation as well. First, increasing the reduction overpotential beyond the potential required to reduce DHAQ to DHAHQ does not increase the rate of capacity loss.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Extending the Lifetime of Organic Flow Batteries via Redox State Management

et al. 2019

View full text Add to dashboard Cite

Redox flow batteries based on quinone-bearing aqueous electrolytes have emerged as promising systems for energy storage from intermittent renewable sources. The lifetime of these batteries is limited by quinone stability. Here, we confirm that 2,6-dihydroxyanthrahydroquinone tends to form an anthrone intermediate that is vulnerable to subsequent irreversible dimerization. We demonstrate quantitatively that this decomposition pathway is responsible for the loss of battery capacity. Computational studies indicate that the driving force for anthrone formation is greater for anthraquinones with lower reduction potentials. We show that the decomposition can be substantially mitigated. We demonstrate that conditions minimizing anthrone formation and avoiding anthrone dimerization slow the capacity loss rate by over an order of magnitude. We anticipate that this mitigation strategy readily extends to other anthraquinone-based flow batteries and is thus an important step toward realizing renewable electricity storage through long-lived organic flow batteries.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Extending the Lifetime of Organic Flow Batteries via Redox State Management

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Moreover, if either product exhibits a more extreme redox potential than the original couple or a similar redox potential with more sluggish kinetics, an apparent capacity fade will be observed for given cycling potential limits. Quinones are susceptible to this mechanism: the disproportionation of anthrahydroquinone (2-electron reduced anthraquinone) to anthrone and anthraquinone was observed during electrochemical reduction of unsubstituted anthraquinone under highly acidic condition . Shi et al also obtained monomers and dimers of 1,8-dimethoxy-10-anthrone upon chemical reduction of 1,8-dimethoxyanthraquinone with sodium borohydride and trifluoroacetic acid .…”

Section: Chemical Decomposition and Capacity Fadementioning

confidence: 65%

Electrolyte Lifetime in Aqueous Organic Redox Flow Batteries: A Critical Review

2020

View full text Add to dashboard Cite

Aqueous organic redox flow batteries (RFBs) could enable widespread integration of renewable energy, but only if costs are sufficiently low. Because the levelized cost of storage for an RFB is a function of electrolyte lifetime, understanding and improving the chemical stability of active reactants in RFBs is a critical research challenge. We review known or hypothesized molecular decomposition mechanisms for all five classes of aqueous redox-active organics and organometallics for which cycling lifetime results have been reported: quinones, viologens, aza-aromatics, iron coordination complexes, and nitroxide radicals. We collect, analyze, and compare capacity fade rates from all aqueous organic electrolytes that have been utilized in the capacity-limiting side of flow or hybrid flow/nonflow cells, noting also their redox potentials and demonstrated concentrations of transferrable electrons. We categorize capacity fade rates as being “high” (>1%/day), “moderate” (0.1–1%/day), “low” (0.02–0.1%/day), and “extremely low” (≤0.02%/day) and discuss the degree to which the fade rates have been linked to decomposition mechanisms. Capacity fade is observed to be time-denominated rather than cycle-denominated, with a temporal rate that can depend on molecular concentrations and electrolyte state of charge through, e.g., bimolecular decomposition mechanisms. We then review measurement methods for capacity fade rate and find that simple galvanostatic charge–discharge cycling is inadequate for assessing capacity fade when fade rates are low or extremely low and recommend refining methods to include potential holds for accurately assessing molecular lifetimes under such circumstances. We consider separately symmetric cell cycling results, the interpretation of which is simplified by the absence of a different counter-electrolyte. We point out the chemistries with low or extremely low established fade rates that also exhibit open circuit potentials of 1.0 V or higher and transferrable electron concentrations of 1.0 M or higher, which are promising performance characteristics for RFB commercialization. We point out important directions for future research.

show abstract

“…49 In our work, during the electrochemical reduction of AQDS (detailed in the next section), we also observed the solution color changing from yellow to green. Electrochemical studies by Beck 47,48 and others on anthraquinone derivatives in nonaqueous and aqueous electrolytes have also suggested the formation of a hydroxyanthraquinone−anthraquinone dimer. 50 Electrochemical Investigation of AQDS Derivatives.…”

Section: S6mentioning

confidence: 97%

Concentration-Dependent Dimerization of Anthraquinone Disulfonic Acid and Its Impact on Charge Storage

et al. 2017

View full text Add to dashboard Cite

9,10-Anthraquinone-2,7-disulfonic acid (AQDS) is considered a benchmark active material for aqueous organic redox flow batteries. At low concentration, AQDS demonstrates two-electron transfer at near ideal electrochemical reversibility; however, at higher concentration, AQDS displays more complex behavior presumably due to the emergence of intermolecular reactions. Here, we systematically examine the electrochemical and physical properties of AQDS solutions using a suite of electrochemical, analytical, and spectroscopic techniques. Depending on the AQDS pretreatment, concentration, solution pH, and electrolyte composition, coupled chemical and electrochemical reactions lead to different charge storage capabilities. To elucidate the underlying cause of these differences, we performed various pretreatments of AQDS, examined chemical speciation by NMR, and investigated the corresponding electrochemical properties through cyclic voltammetry and bulk electrolysis. In all cases, reversible intermolecular dimerization was detected at solution concentrations greater than 10 mM. Moreover, we found that the charge state of the formed dimers was dependent on the AQDS pretreatment and the solution pH. Under acidic conditions, 1.5 electrons per molecule of AQDS were reversibly accessible, whereas under buffered mild-alkaline conditions, only one electron per molecule of AQDS was accessible. Because of insufficient proton concentration, AQDS did not cycle reversibly in unbuffered neutral electrolyte. Even when employing chemical oxidants during a chemical titration, charge storage of two electrons per molecule could not be realized. We hypothesize that adduct formation between AQDS and CO2, along with solution pH, play important roles in the charge accessibility.

show abstract

On the Mechanism of the Cathodic Reduction of Anthraquinone to Anthrone

Cited by 34 publications

References 19 publications

Extending the Lifetime of Organic Flow Batteries via Redox State Management

Extending the Lifetime of Organic Flow Batteries via Redox State Management

Electrolyte Lifetime in Aqueous Organic Redox Flow Batteries: A Critical Review

Concentration-Dependent Dimerization of Anthraquinone Disulfonic Acid and Its Impact on Charge Storage

Contact Info

Product

Resources

About