Tetrathiafulvalene (TTF) derivatives as catholytes for dual-type redox flow batteries: molecular engineering enables high energy density and cyclability

Wang, Xiao; Lashgari, Amir; Siwakoti, Rabin; Gautam, Rajeev K.; McGrath, Jack J.; Sarkar, Prasenjit; Naber, Grace; Chai, Jingchao; Jiang, Jianbing Jimmy

doi:10.1039/d3ta03606e

“…For example, annulated rings have been used to prevent degradation by electrophilic or nucleophilic addition to the quinone during cycling . Heteroaromatic molecules are often explored due to their redox properties, e.g., tetrathiofulvalene-, , phenazine-, − or quinoxaline-based electrolytes, − or for the ability to modify the charge mobility, energy gaps, and intermolecular interactions . One such example can be seen in the study of fused heteroaromatics for organic electrodes in lithium-ion batteries (LIBs), , where the electrochemical properties of a series of fused heteroaromatics, including bis-furan (BFFD, Figure ), bis-thiophene (BDTD, Figure ), and bis-pyridine (PID, Figure ) quinone derivatives were studied and compared to AQ (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Exploring the Landscape of Heterocyclic Quinones for Redox Flow Batteries

Jethwa,

Hey,

Kerber

et al. 2023

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

Redox flow batteries (RFBs) rely on the development of cheap, highly soluble, and high-energy-density electrolytes. Several candidate quinones have already been investigated in the literature as two-electron anolytes or catholytes, benefiting from fast kinetics, high tunability, and low cost. Here, an investigation of nitrogen-rich fused heteroaromatic quinones was carried out to explore avenues for electrolyte development. These quinones were synthesized and screened by using electrochemical techniques. The most promising candidate, 4,8-dioxo-4,8-dihydrobenzo[1,2-d:4,5-d′]bis ([1,2,3]triazole)-1,5-diide (−0.68 V(SHE)), was tested in both an asymmetric and symmetric full-cell setup resulting in capacity fade rates of 0.35% per cycle and 0.0124% per cycle, respectively. In situ ultraviolet-visible spectroscopy (UV−Vis), nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) spectroscopies were used to investigate the electrochemical stability of the charged species during operation. UV− Vis spectroscopy, supported by density functional theory (DFT) modeling, reaffirmed that the two-step charging mechanism observed during battery operation consisted of two, single-electron transfers. The radical concentration during battery operation and the degree of delocalization of the unpaired electron were quantified with NMR and EPR spectroscopy.

show abstract

High‐Voltage Catholyte for High‐Energy‐Density Nonaqueous Redox Flow Battery

McGrath,

Gautam,

Wang

et al. 2024

Angewandte Chemie

0

View full text Add to dashboard Cite

Redox flow batteries (RFBs) with high energy densities are essential for efficient and sustainable long‐term energy storage on a grid scale. To advance the development of nonaqueous RFBs with high energy densities, a new organic RFB system employing a molecularly engineered tetrathiafulvalene derivative ((PEG3/PerF)‐TTF) as a high energy density catholyte was developed. When paired with a lithium metal anode, the two‐electron‐active (PEG3/PerF)‐TTF catholyte produced a cell voltage of 3.56 V for the first reduction and 3.92 V for the second reduction process. In cyclic voltammetry and flow cell tests, the redox chemistry exhibited excellent cycling stability. The Li|(PEG3/PerF)‐TTF batteries, with concentrations of 0.1 M and 0.5 M, demonstrated capacity retention rates of ~94% (99.87% per cycle, 97.52% per day) and 90% (99.93% per cycle, 99.16% per day), and the average Coulombic efficiencies of 99.38% and 98.35%, respectively. The flow cell achieved a high power density of 129 mW/cm2. Furthermore, owing to the high redox potential and solubility of (PEG3/PerF)‐TTF, the flow cell attained a high operational energy density of 72 Wh/L (100 Wh/L theoretical). A 0.75 M flow cell exhibited an even higher operational energy density of 96 Wh/L (150 Wh/L theoretical).

show abstract

High‐Voltage Catholyte for High‐Energy‐Density Nonaqueous Redox Flow Battery

McGrath,

Gautam,

Wang

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

Redox flow batteries (RFBs) with high energy densities are essential for efficient and sustainable long‐term energy storage on a grid scale. To advance the development of nonaqueous RFBs with high energy densities, a new organic RFB system employing a molecularly engineered tetrathiafulvalene derivative ((PEG3/PerF)‐TTF) as a high energy density catholyte was developed. When paired with a lithium metal anode, the two‐electron‐active (PEG3/PerF)‐TTF catholyte produced a cell voltage of 3.56 V for the first reduction and 3.92 V for the second reduction process. In cyclic voltammetry and flow cell tests, the redox chemistry exhibited excellent cycling stability. The Li|(PEG3/PerF)‐TTF batteries, with concentrations of 0.1 M and 0.5 M, demonstrated capacity retention rates of ~94% (99.87% per cycle, 97.52% per day) and 90% (99.93% per cycle, 99.16% per day), and the average Coulombic efficiencies of 99.38% and 98.35%, respectively. The flow cell achieved a high power density of 129 mW/cm2. Furthermore, owing to the high redox potential and solubility of (PEG3/PerF)‐TTF, the flow cell attained a high operational energy density of 72 Wh/L (100 Wh/L theoretical). A 0.75 M flow cell exhibited an even higher operational energy density of 96 Wh/L (150 Wh/L theoretical).

show abstract

Tetrathiafulvalene (TTF) derivatives as catholytes for dual-type redox flow batteries: molecular engineering enables high energy density and cyclability

Abstract: Redox flow batteries (RFBs) have received increasing attention on large-scale energy storage owing to their ability to decouple energy and power. Despite remarkable progress, the application of RFBs is greatly...

Cited by 6 publications

References 100 publications

Exploring the Landscape of Heterocyclic Quinones for Redox Flow Batteries

Exploring the Landscape of Heterocyclic Quinones for Redox Flow Batteries

High‐Voltage Catholyte for High‐Energy‐Density Nonaqueous Redox Flow Battery

High‐Voltage Catholyte for High‐Energy‐Density Nonaqueous Redox Flow Battery

Contact Info

Product

Resources

About