A solution for scalable-flow batteries Flow batteries, in which the redox active components are held tanks separate from part of cell, offer a scalable route storing large quantities energy. challenge their large-scale development is to avoid formulations that depend on toxic transition metal ions. Lin et al. show quinones can be dissolved alkaline solutions and coupled with ferricyanides make flow cell battery (see Perspective by Perry). This gives scope developing cells very low costs,...

Inspired by the electron transfer properties of quinones in biological systems, we recently showed that are also very promising electroactive materials for stationary energy storage applications. Due to practically infinite chemical space organic molecules, discovery additional or other redox-active molecules applications is an open field inquiry. Here, introduce a high-throughput computational screening approach applied accelerated study total 1710 quinone (Q) and hydroquinone (QH2) (i.e.,...

Anthraquinone derivatives are being considered for large scale energy storage applications because of their chemical tunability and rapid redox kinetics. The authors investigate four anthraquinone as negative electrolyte candidates an aqueous quinone‐bromide flow battery: anthraquinone‐2‐sulfonic acid (AQS), 1,8‐dihydroxyanthraquinone‐2,7‐disulfonic (DHAQDS), alizarin red S (ARS), 1,4‐dihydroxyanthraquinone‐2,3‐dimethylsulfonic (DHAQDMS). standard reduction potentials all lower than that...

The iron–chromium (FeCr) redox flow battery (RFB) was among the first batteries to be investigated because of low cost electrolyte and 1.2 V cell potential. We report effects chelation on solubility electrochemical properties Fe3+/2+ couple. An Fe utilizing diethylenetriaminepentaacetic acid (DTPA) exhibits efficient high-performance cycling at pH 9 versus a Cr-chelate complex 1,3-diaminopropanetetraacetic (PDTA). FeDTPA can cycled concentrations up 1.35 M, equating storage capacity 36.2 Ah...

Ferrocyanides and ferricyanides are among the most employed positive electrolyte materials in aqueous flow battery research, but limited solubility of commonly available sodium potassium salts is a critical factor limiting application at scale. Here, we systematically study cation-dependent these and, importantly, stability anion solution. For Li4Fe(CN)6, report maximum 2.3 M show stable cycling 2 symmetric cell, corresponding to capacities 54 Ah L−1, over 200 days. We also demonstrate...

Using satellite imagery we show that the installation footprint of grid-scale lithium-ion batteries is often comparable to much less energy-dense technologies such as aqueous battery systems.

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...

Olefin complexes (silox)3M(ole) (silox = tBu3SiO; M Nb (1-ole), Ta (2-ole); ole C2H4, C2H3Me, C2H3Et, C2H3C6H4-p-X (X OMe, H, CF3), C2H3tBu, cC5H8, cC6H10, cC7H10 (norbornene)) rearrange to alkylidene isomers (silox)3M(alk) (M (1alk), (2alk); alk CHMe, CHEt, CHnPr, CHCH2C6H4-p-X CF3 (Ta only)), CHCH2tBu, (norbornylidene)). Kinetics and labeling experiments suggest that the rearrangement proceeds via a δ-abstraction on silox CH bond by β-olefin carbon give (silox)2RM(κ2-O,C-OSitBu2CMe2CH2)...

We have demonstrated the performance of an aqueous redox flow battery composed a negative electrode consisting couple between anthraquinone di-sulfonate and its corresponding hydroquinone, positive hydrobromic acid bromine. The peak power density is approximately 0.6 W/cm 2 . After 750 deep cycles, average discharge capacity retention 99.84% per cycle current efficiency 98.35%.

The synthesis, characterization, and photophysical properties of 4- 6-coordinate Bi3+ coordination complexes are reported. Bi(bzq)3 (1) [Bi(bzq)2]Br (2) (bzq = benzo[h]quinoline) synthesized by reaction 9-Li-bzq with BiCl3 BiBr3, respectively. Absorption spectroscopy, electrochemistry, DFT studies suggest that 1 has 42% Bi 6s character in its highest-occupied molecular orbital (HOMO) as a result six σ* interactions the bzq ligands. Excitation at 450 nm results broad emission feature 520 nm,...

By tailoring the coordination sphere of vanadium to accommodate a 7-coordinate geometry, highly soluble (>1.3 M) and reducing (-1.2 V vs Ag/AgCl) flow battery electrolyte is generated from [V(DTPA)]2-/3- (DTPA = diethylenetriaminepentaacetate). Bulk spectroelectrochemistry performed in situ assess material properties both oxidized reduced states. Flow batteries are assembled near neutral pH conditions operated with discharge energy densities 12.5 Wh L-1 high efficiency. Further, first...

High power density operation of redox flow batteries (RFBs) is essential for lowering system costs, but until now, only acid-based chemistries have achieved such performance, primarily due to rapid membrane proton (H+) transport. Here, we report a neutral pH RFB using the highly reducing Cr-(1,3-propylenediaminetetraacetate) (CrPDTA) complex that achieves acid-like performance while utilizing potassium ion (K+) We investigate resistance components and demonstrate high consistent K+...

The reaction of Co(2)(mesityl)(4) with acetonitrile leads to the formation a planar, low spin, bis-β-diketiminate cobalt(II) complex, (1-mesitylbutane-1,3-diimine)(2)Co (1). EPR spectroscopy, magnetic studies, and DFT calculations reveal Co(II) ion reside in tetragonal ligand field (2)B(2)(d(yz))(1) ground state electronic configuration. Oxidation 1 ferrocenium hexafluorophosphate furnishes (1-mesitylbutane-1,3-diimine)(2)Co(THF)(2)PF(6) (2). absence significant changes metal-ligand bond...

The assembly and testing of a rechargeable 3 V lithium-ion battery in the common 2032 coin cell format is demonstrated classroom environment without use expensive complex air-free equipment. procedure has been developed to eliminate highly toxic materials flammable solvents, can be accomplished 15 min, designed as inexpensive, safe, simple possible. repeatedly charged with cheap USB-powered charger used power an LED tea candle or similar device. A stopwatch multimeter estimate capacity...

Here, we outline some basic pitfalls in the electrochemical investigation of aqueous metal complexes, advocate for use bulk electrolysis redox flow cells electrolyte analysis, and demonstrate methods operation performance a lab scale battery.

Metal electrocatalysts have been reported to improve the electron transfer kinetics of aqueous redox flow battery electrolytes on various types carbon electrodes. In this work, we electrodeposited bismuth metal onto a paper anode containing our previously polyaminocarboxylate-chelated chromium electrolyte. Depositing 0.58 mg cm –2 enabled an electrochemically reversible for Cr(II)/Cr(III) couple, resulting in 3.9% voltage efficiency increase over ten cycles at 100 mA across 80% state charge...

The reaction of Na(OSi(t)Bu(2)Me) with CrCl(3) yields solid [Cr(OSi(t)Bu(2)Me)(3)](n) (1), which can be crystallized in the presence excess to yield [Na(THF)][Cr(OSi(t)Bu(2)Me)(4)] (2). This complex is oxidized Cr(OSi(t)Bu(2)Me)(4) (3), a crystalline chromium(IV) siloxide that air- and moisture-stable. Electronic spectroscopic analysis absorption spectrum 3 indicates particularly weak ligand field (Δ(T) = 7940 cm(-1)) covalent Cr-O bonding. provides first structural characterization...

The synthesis of a sterically encumbered β-diketone ligand (Aracac) substituted with 2,6-(2,4,6-Me3C6H2)2C6H3 is described. Coordination complexes the type M(Aracac)2Cl(solv) (M = Ti, V, Cr; solv THF, CH3CN) were prepared by reaction Aracac MCl3 Cr) or TiCl4 to generate Ti(Aracac)2Cl2, followed reduction. These show trend alternating cis/trans geometric preference increasing dn electron count (n 0, 1, 2, 3), which rationalized in part unusual ability β-diketonates behave as either weak π...

Bulky β-diketones have rarely exceeded dipivaloylmethane (DPM) in steric demand, largely due to synthetic limitations of the Claisen condensation. This work demonstrates hindered acid chlorides be selective electrophiles noncoordinating solvents for condensations with enolates. An improved synthesis DPM is described (90% yield), and crowded featuring bulky o-biphenyl or m-terphenyl fragments were prepared good excellent yields. These compounds are anticipated a profile far greater than that...

The highly reducing CrII-(1,3-propylenediaminetetraacetate) (CrPDTA) complex (-1.1 V vs SHE) has been isolated from aqueous solution and the solid-state structure is described. reduced CrIIPDTA characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, UV-vis magnetic moment, density functional theory calculations. concentration profile, state of charge, pH CrPDTA electrolyte were monitored in a flow battery system situ absorption spectroscopy probe....

Metal coordination complexes of the sterically hindered β-diketonate, 2,6-dimesitylbenzoyl pinacolone (esac), are reported for Co, Ni, Cu, and Zn. All four form ML2-type with typical behavior late-metal β-diketonates, however effects on established electrochemistry reactivity vary somewhat per metal. For example, striking chemical electrochemical inertness CoII(esac)2 to oxidation disproportionation is atypical. Conversely, CuII(esac)2 rather relative other CuII(β-diketonate)2 complexes....