Dual function organic active materials for nonaqueous redox flow batteries

Attanayake, N. Harsha; Liang, Zhiming; Wang, Yilin; Kaur, Aman Preet; Parkin, Sean; Mobley, Justin K.; Ewoldt, Randy H.; Landon, James; Odom, Susan A.

doi:10.1039/d0ma00881h

Cited by 35 publications

(69 citation statements)

References 57 publications

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“…Redox flow batteries offer advantages over other electrochemical energy storage methods due to their long calendar life, simple design, and scalability [1,2] . While aqueous redox flow batteries have been extensively studied for decades, non‐aqueous systems have received increased attention over the last ten years, offering operating voltages exceeding the 1.5 V limit of water and the use of a myriad of electrochemically active molecules that are insoluble in water [3–5] …”

Section: Introductionmentioning

confidence: 99%

“…[1,2] While aqueous redox flow batteries have been extensively studied for decades, non-aqueous systems have received increased attention over the last ten years, offering operating voltages exceeding the 1.5 V limit of water and the use of a myriad of electrochemically active molecules that are insoluble in water. [3][4][5] Electroactive species for non-aqueous redox flow batteries have spanned the gamut, from small organic molecules, to metal coordination complexes (MCCs), to large metal-based clusters, to hybrid systems. [6][7][8][9] A recent review by Palmer et al summarizes the variety of metal-based charge carriers used in nonaqueous flow batteries in the past 5 years.…”

Section: Introductionmentioning

confidence: 99%

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Elucidating Instabilities Contributing to Capacity Fade in Bipyridine‐Based Materials for Non‐aqueous Flow Batteries

et al. 2022

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Metal‐based non‐aqueous redox flow batteries have the potential for long‐term energy storage if stability requirements can be achieved. One such stability issue in metal coordination complexes arises from ligand shedding in the anolyte upon reduction. Recognizing that the free ligands are relatively more stable than the metal coordination complex under highly reducing conditions, we evaluated a family of metal‐free bipyridinium materials as flow battery anolytes with the corresponding iron coordination complex as the catholyte. Bipyridinium compounds were functionalized for increased electrochemical stability, cycled in flow cells to understand efficiencies, and analyzed for degradation products. Methylation of the bipyridine nitrogens increased electrochemical stability yet left the reduced molecule susceptible to radical‐induced bond cleavage. Subsequent functionalization of bipyridine with carbomethoxy groups resulted in good battery performance with 96 % Coulombic and 90 % voltage efficiency, and improved cycling stability over a methoxy‐substituted anolyte with 14 % vs 36 % capacity fade in the first charge‐discharge cycle.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Elucidating Instabilities Contributing to Capacity Fade in Bipyridine‐Based Materials for Non‐aqueous Flow Batteries

et al. 2022

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“…[7,11,15,28] Several research teams have made progress in the molecular engineering of next-generation phenothiazine derivatives (Figure 1). [11,26,[28][29][30][31][32] Odom and co-workers conducted early investigations of the parent N-ethyl phenothiazine (1)and disclosed that it suffers from low solubility (0.1 Mfor the neutral molecule and 0.1 Mf or the radical cation in TEABF 4 /MeCN) and an unstable second oxidation. [26] As shown in Figure 1A,t heir team initially used molecular engineering to address each of these individual properties.For instance,t hey showed that replacing the N-ethyl substituent with an N-oligoethylene oxide (OEO) chain (1-OEO) resulted in dramatically enhanced solubility for both the neutral (miscible) and radical cation (0.5 M) in TEABF 4 / MeCN.H owever,t he second oxidative couple of 1-OEO remained unstable,s oo nly single-electron cycling could be achieved.…”

Section: Introductionmentioning

confidence: 99%

Development of High Energy Density Diaminocyclopropenium‐Phenothiazine Hybrid Catholytes for Non‐Aqueous Redox Flow Batteries

et al. 2021

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This report describes the design of diaminocyclopropenium-phenothiazine hybrid catholytes for non-aqueous redox flowb atteries. The molecules are synthesized in ar apid and modular fashion by appending ad iaminocyclopropenium (DAC)s ubstituent to the nitrogen of the phenothiazine.C ombining av ersatile C-N coupling protocol (which provides access to diverse derivatives) with computation and structure-property analysis enabled the identification of ac atholyte that displays stable two-electron cycling at potentials of 0.64 and 1.00 Vvs. Fc/Fc + as well as high solubility in all oxidation states (! 0.45 Mi nT BAPF 6 /MeCN). This catholyte was deployed in ah igh energy density two-electron RFB,e xhibiting > 90 %c apacity retention over 266 hours of flowc ell cycling at > 0.5 Me lectron concentration.

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“…[26][27][28] Recently, anolytes such as N-methyl phthalimide, [29,30] 9flurenonone, [31] benzothiadiazoles, [32] camphoquinone, [33] trimethyl-quinoxaline, [34,35] PTIO, [36] 4-benzoylpyridinium derivatives, [37,38] 2-methylbenzophenone [39] and viologen derivatives were developed. [40,41] However, most of these anolytes exhibited low cycle life, possibly due to poor (electro)chemical stability, when used in ONRFBs.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Evaluation of Diketopyrrolopyrrole Derivatives for Nonaqueous Redox Flow Batteries

Sharma

Rathod

Yadav

et al. 2021

Chemistry A European J

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Redox flow batteries (RFBs) employing nonaqueous electrolytes could potentially operate at much higher cell voltages, and therefore afford higher energy and power densities, than RFBs employing aqueous electrolytes. The development of such high‐voltage nonaqueous RFBs requires anolytes that are electrochemically stable, especially in the presence of traces of oxygen and/or moisture. The inherent atmospheric reactivity of anolytes mandates judicious molecular design with high electron affinity and electrochemical stability. In this study, diketopyrrolopyrrole (DPP)‐based TDPP‐Hex‐CN4 is proposed as a stable redox‐active molecule for anolytes in nonaqueous organic RFBs. We demonstrate organic RFBs using TDPP‐Hex‐CN4 as anolyte with unisol blue (UB) 1,4‐bis(isopropylamino)anthraquinone and 1,4‐di‐tert‐butyl‐2,5‐bis(2‐methoxyethoxy)benzene (DBBB) as catholytes. Cyclic voltammetry measurements with scans repeated over 200 cycles were performed to establish the electrochemical stability of the redox pairs. Symmetric flow‐cell studies show that TDPP‐Hex‐CN4 exhibits stable capacity up to 700 cycles. Redox flow cells employing TDPP‐Hex‐CN4 /UB and TDPP‐Hex‐CN4/DBBB as redox pairs demonstrate that DPP derivatives are propitious materials for anolytes in all organic nonaqueous RFBs.

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Dual function organic active materials for nonaqueous redox flow batteries

Abstract: X-ray crystal structures of a phenothiazine posolyte and viologen negolyte and cyclic voltammograms of a solution containing both compounds.

Cited by 35 publications

References 57 publications

Elucidating Instabilities Contributing to Capacity Fade in Bipyridine‐Based Materials for Non‐aqueous Flow Batteries

Elucidating Instabilities Contributing to Capacity Fade in Bipyridine‐Based Materials for Non‐aqueous Flow Batteries

Development of High Energy Density Diaminocyclopropenium‐Phenothiazine Hybrid Catholytes for Non‐Aqueous Redox Flow Batteries

Electrochemical Evaluation of Diketopyrrolopyrrole Derivatives for Nonaqueous Redox Flow Batteries

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