Abstract An extremely stable, energy‐dense (53.6 Ah L −1 , 2 m transferrable electrons), low crossover (permeability of <1 × 10 −13 cm s using Nafion 212 (Nafion is a trademark polymer from DuPont)), and potentially inexpensive anthraquinone with 2‐2‐propionate ether structure (abbreviated 2‐2PEAQ) synthesized extensively evaluated under practically relevant conditions for use in the negolyte an aqueous redox flow battery. 2‐2PEAQ shows high stability fade rate 0.03–0.05% per day at...

Organic reactants are promising candidates for long-lifetime redox flow batteries, and synthetic chemistry unlocks a wide design space new molecules. Minimizing crossover of these molecules through ion exchange membranes is one important consideration, but the ways in which rate depends on structure crossing species remain unclear. Here, we contribute systematic evaluation size- charge-based effects dilute-solution small molecule permeability Nafion NR212 cation membrane. We found that...

We assess the suitability of potassium ferri-/ferrocyanide as an electroactive species for long-term utilization in aqueous organic redox flow batteries. A series electrochemical and chemical characterization experiments was performed to distinguish between structural decomposition apparent capacity fade solutions used capacity-limiting side a battery. Our results indicate that, contrast with previous reports, no occurs at tested pH values high 14 dark or diffuse indoor light. Instead, takes...

Abstract Aqueous organic redox flow batteries are promising candidates for large‐scale energy storage. However, the design of stable and inexpensive electrolytes is challenging. Here, we report a highly stable, low potential, potentially negolyte species, sodium 3,3′,3′′,3′′′‐((9,10‐anthraquinone‐2,6‐diyl)bis(azanetriyl))tetrakis(propane‐1‐sulfonate) (2,6‐N‐TSAQ), which synthesized in single step from precursors. Pairing 2,6‐N‐TSAQ with potassium ferrocyanide at pH=14 yielded battery highest...

An anthraquinone featuring a chiral carboxylate-capped methyl-branched side chain with an ether linkage, 2,2′-((9,10-dioxo-9,10-dihydroanthracene-2,6-diyl)bis(oxy))dipropionic acid (2,6-D2PEAQ), was synthesized and evaluated for use in aqueous redox flow batteries. It found to have extraordinary solubility of 2 M (4 electrons), corresponding theoretical volumetric capacity 107.2 Ah/L the negative electrolyte, which is 10 times that its unbranched counterpart. The 2,6-D2PEAQ molecule...

Abstract An iron complex, tris(4,4′‐bis(hydroxymethyl)‐2,2′‐bipyridine) dichloride is reported, which operates at near‐neutral pH with a redox potential of 0.985 V versus SHE. This high compound employed in the posolyte an aqueous flow battery, paired bis(3‐trimethylammonio)propyl viologen tetrachloride negolyte, exhibiting open‐circuit voltage 1.3 pH. It demonstrates excellent cycling performance low temporal capacity fade rate 0.07% per day over 35 days cycling. The extended lifetime...

Redox flow batteries (RFBs) can achieve long lifetimes and high performance when employing highly selective conductive membranes. Neutral alkaline RFBs suffer from higher resistances due to lower cation conductivity, compared acidic utilizing proton transport. We report the use of a sulfonated Diels-Alder poly(phenylene) membrane that exhibits low stable potassium area specific resistance efficiency RFB cycling relative Nafion, as well undetectable ferricyanide crossover. An (pH 12) organic...

Separation of carbon dioxide (CO2) from point sources or directly the atmosphere can contribute crucially to climate change mitigation plans in coming decades. A fundamental practical limitation for current strategies is considerable energy cost required regenerate sorbent and release captured CO2 storage utilization. photochemically driven system that demonstrates efficient passive capture on-demand triggered by sunlight as sole external stimulus would provide an attractive alternative....

Kinetic isotope effect (KIE) was used to study the rate-determining step for oxygen reduction reaction (ORR) on dispersed Pt/C electrocatalyst and polycrystalline Pt (Pt-poly). KIE is defined as ratio of kinetic current measured in protonated electrolyte versus deuterated electrolyte, with values larger than one indicating proton participation step. The poisoning anions platinum rate determining investigated by assessing perchloric (non-poisoning) sulfuric acid-based electrolytes. kinetics...

Volumetrically unbalanced compositionally symmetric cell cycling with potentiostatic (CV) or galvanostatic-with-potential-hold (CCCV) protocols is a rigorous technique for evaluating the calendar lifetime of reactants redox flow batteries.

Aqueous redox flow batteries require long-term stable molecules for electrical energy storage. Anthraquinones, especially ether bond-decorated ones, experience two dominant decomposition pathways, including side-chain loss and anthrone formation. With the aid of DFT calculations, we designed an anthraquinone (3-NH2-2-2PEAQ) bearing substituent a neighboring NH2 group, which suppresses both these mechanisms exhibits high solubility 1.1 M. When paired with ferrocyanide in full cell, this...

This study presents thin-film electrode design for polymer electrolyte fuel cells (PEFCs) prepared by atomic layer deposition (ALD). Due to structural alignment and controlled pore sizes, this Pt ALD nanoelectrode array is a promising model ionomer-free transport reaction kinetics studies. The fabrication process used deposit monolayers of onto sacrificial substrate dissociative chemisorption in self-assembling reaction. A novel thermal exposure mode nanostructures anodized aluminum oxide...

Membrane transport properties are crucial for electrochemical devices, and these influenced by the composition concentration of electrolyte in contact with membrane. We apply this general membrane-electrolyte system approach to alkaline flow batteries, studying conductivity ferricyanide crossover Nafion E-620. report undetectable as-received E-620 after both sodium potassium exchange, but high permeability 10^−7 10^−8 cm^2 s^−1 subjected pre-treatment prevalent battery literature. show how...

Volumetrically unbalanced compositionally symmetric cell cycling with potentiostatic (CV) or galvanostatic-with-potential-hold (CCCV) protocols is a rigorous technique for evaluating the calendar lifetime of reactants redox flow batteries. Here, we evaluate influence reactant crossover through membrane on behavior. We tested cells anthraquinone disulfonic acid (AQDS) Nafion membranes varied thickness and manufacture (NR211, NR212, N115, N117, ranging 25–183 μm). Membranes were both...

The attraction of aqueous organic redox flow batteries (AORFBs) lies in the potential for low mass-production cost and long lifetime molecules. To reach cell potentials >1.0 V, several AORFBs have employed ferri/ferrocyanide couple as posolyte alkaline conditions. Recent works reported significant amounts capacity fade this at high pH, attributed either to chemical decomposition associated with cyanide ligand dissociation irreversible hydroxylation iron complex [1,2], or due unbalancing...

Membrane transport properties are crucial for electrochemical devices, and these influenced by the composition concentration of electrolyte in contact with membrane. We apply this general membrane-electrolyte system approach to alkaline flow batteries, studying conductivity ferricyanide crossover Nafion E-620. report undetectable as-received E-620 after both sodium potassium exchange but high permeability 10-7 10-8 cm2 s-1 subjected pretreatment prevalent battery literature. show how mass...

Aqueous redox flow batteries (ARFBs) constitute a promising technology for grid-scale electricity storage, but it is challenging to implement cell voltages exceeding the 1.23 V thermodynamic water splitting window with high Coulombic efficiency and long lifetime. pH decoupling – creation of difference between negolyte posolyte can broaden operating voltage improve long-term operational stability. This penalizes efficiency, however, due acid-base crossover induced by gradient. As varies...

Aqueous organic redox flow batteries are promising candidates for large-scale energy storage. However, the design of stable and inexpensive electrolytes is challenging. Here, we report a highly stable, low potential, potentially negolyte species, sodium 3,3',3'',3'''-((9,10-anthraquinone-2,6-diyl)bis(azanetriyl))tetrakis(propane-1-sulfonate) (2,6-N-TSAQ), which synthesized in single step from precursors. Pairing 2,6-N-TSAQ with potassium ferrocyanide at pH 14 yielded battery highest...

The library of redox-active organics that are potential candidates for electrochemical energy storage in flow batteries is exceedingly vast, necessitating high-throughput characterization molecular lifetimes. Demonstrated extremely stable chemistries require accurate yet rapid cell cycling tests, a demand often frustrated by time-denominated capacity fade mechanisms. We have developed setup elevated temperature redox batteries, providing new dimension parameter space to explore. utilize it...

The library of redox-active organics that are potential candidates for electrochemical energy storage in flow batteries is exceedingly vast, necessitating high-throughput characterization molecular lifetimes. Demonstrated extremely stable chemistries require accurate yet rapid cell cycling tests, a demand often frustrated by time-denominated capacity fade mechanisms. We have developed setup elevated temperature redox batteries, providing new dimension parameter space to explore. utilize it...

Bipolar membranes (BPMs), consisting of an anion exchange polymer membrane layer, a cation with catalytic interfacial layer in between, enable electrolysis cells large difference pH between adjacent chambers. This gradient is working principle number devices for energy and sustainability: acid/base batteries store release by building depleting difference; BPM electrodialysis reactors capture CO 2 alkaline electrolytes acidifying; H O may employ pH-decoupled electrodes to avoid precious metal...

Aqueous organic redox flow batteries (AORFBs) have emerged as potentially disruptive technologies for the storage of electrical energy from intermittent renewable sources. With goal cost-effective, safe, and scalable stationary long duration systems, AORFBs could become preferred over Li-ion grid-scale due to their inherent non-flammability, lack materials scarcity fluctuations, intrinsic decoupling power capacities. Our group has demonstrated that calendar life, rather than cycle limits...

Aqueous redox flow batteries (ARFBs) constitute a promising technology for grid-scale electricity storage, but it is challenging to implement cell voltages exceeding the 1.23 V thermodynamic water splitting window with high Coulombic efficiency and long lifetime. pH decoupling – creation of difference between negolyte posolyte can broaden operating voltage improve long-term operational stability. This penalizes efficiency, however, due acid-base crossover induced by gradient. As varies...