Blatter Radicals as Bipolar Materials for Symmetric Redox-Flow Batteries

2021 ◽  
Author(s):  
Jelte Steen ◽  
Jules Nuismer ◽  
Vytautas Eiva ◽  
Albert Wiglema ◽  
Nicolas Daub ◽  
...  
Keyword(s):  
Active Material ◽  
Chemical Degradation ◽  
Limiting Factors ◽  
Redox Potentials ◽  
X Ray Crystallography ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
The Stability ◽  
Bipolar Electrochemistry

Redox-active organic molecules are promising charge-storage materials for redox-flow batteries (RFBs), but material crossover between posolyte/negolyte and chemical degradation are limiting factors in the performance of all-organic RFBs. We demonstrate that the bipolar electrochemistry of 1,2,4-benzotriazin-4-yl (Blatter) radicals allows construction of batteries with symmetric electrolyte composition. Cyclic voltammetry shows that these radicals retain reversible bipolar electrochemistry also in the presence of water. The redox potentials of derivatives with a C(3)-CF3 substituent are least affected by water and, moreover, these compounds show >90% capacity retention after charge/discharge cycling in a static H-cell for seven days (ca. 100 cycles). Testing these materials in a flow regime at 0.1 M concentration of active material confirmed the high cycling stability under conditions relevant for RFB operation, and demonstrated that polarity inversion in a symmetric flow battery may be used to rebalance the cell. Chemical synthesis provides insight in the nature of the charged species by spectroscopy and (for the oxidized state) X-ray crystallography. The stability of these compounds in all three states of charge highlights the potential for application in symmetric organic redox-flow batteries.

TEMPO/Phenazine Combi-Molecule: A Redox-Active Material for Symmetric Aqueous Redox-Flow Batteries

2016 ◽  
Vol 1 (5) ◽  
pp. 976-980 ◽  
Author(s):  
Jan Winsberg ◽  
Christian Stolze ◽  
Simon Muench ◽  
Ferenc Liedl ◽  
Martin D. Hager ◽  
...  
Keyword(s):  
Active Material ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries

scholarly journals Too Much of a Good Thing? Assessing Performance Tradeoffs of Two-Electron Compounds for Redox Flow Batteries

2021 ◽  
Author(s):  
Bertrand Neyhouse ◽  
Alexis Fenton Jr ◽  
Fikile Brushett
Keyword(s):  
Electron Transfer ◽  
Systems Engineering ◽  
Mass Transfer Rate ◽  
Electrode Polarization ◽  
Redox Potentials ◽  
Electron Transfer Mechanism ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
Electron Compounds

<p>Engineering redox-active compounds to support stable multi-electron transfer is an emerging strategy for enhancing the energy density and reducing the cost of redox flow batteries (RFBs). However, when sequential electron transfers occur at disparate redox potentials, increases in electrolyte capacity are accompanied by decreases in voltaic efficiency, restricting the viable design space. To understand these performance tradeoffs for two-electron compounds specifically, we apply theoretical models to investigate the influence of the electron transfer mechanism and redox-active species properties on galvanostatic processes. First, we model chronopotentiometry at a planar electrode to understand how the electrochemical response and associated concentration distributions depend on thermodynamic, kinetic, and mass transport factors. Second, using a zero-dimensional galvanostatic charge / discharge model, we assess the effects of these key descriptors on performance for a single half-cell. Specifically, we examine how different properties (i.e., average of the two redox potentials, difference between the two redox potentials, charging rate, mass transfer rate, and comproportionation rate) affect the electrode polarization and voltaic efficiency. Finally, we extend the galvanostatic model to include two-electron compounds in both half-cells, demonstrating compounding voltage losses for a full cell. These results evince limitations to the applicability of multi-electron compounds—as such, we suggest new directions for molecular and systems engineering that may improve the prospects of these materials within RFBs.<b></b></p>

scholarly journals Too Much of a Good Thing? Assessing Performance Tradeoffs of Two-Electron Compounds for Redox Flow Batteries

2021 ◽  
Author(s):  
Bertrand Neyhouse ◽  
Alexis Fenton Jr ◽  
Fikile Brushett
Keyword(s):  
Electron Transfer ◽  
Systems Engineering ◽  
Mass Transfer Rate ◽  
Electrode Polarization ◽  
Redox Potentials ◽  
Electron Transfer Mechanism ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
Electron Compounds

<p>Engineering redox-active compounds to support stable multi-electron transfer is an emerging strategy for enhancing the energy density and reducing the cost of redox flow batteries (RFBs). However, when sequential electron transfers occur at disparate redox potentials, increases in electrolyte capacity are accompanied by decreases in voltaic efficiency, restricting the viable design space. To understand these performance tradeoffs for two-electron compounds specifically, we apply theoretical models to investigate the influence of the electron transfer mechanism and redox-active species properties on galvanostatic processes. First, we model chronopotentiometry at a planar electrode to understand how the electrochemical response and associated concentration distributions depend on thermodynamic, kinetic, and mass transport factors. Second, using a zero-dimensional galvanostatic charge / discharge model, we assess the effects of these key descriptors on performance for a single half-cell. Specifically, we examine how different properties (i.e., average of the two redox potentials, difference between the two redox potentials, charging rate, mass transfer rate, and comproportionation rate) affect the electrode polarization and voltaic efficiency. Finally, we extend the galvanostatic model to include two-electron compounds in both half-cells, demonstrating compounding voltage losses for a full cell. These results evince limitations to the applicability of multi-electron compounds—as such, we suggest new directions for molecular and systems engineering that may improve the prospects of these materials within RFBs.<b></b></p>

Mapping the frontiers of quinone stability in aqueous media: implications for organic aqueous redox flow batteries

2019 ◽  
Vol 7 (20) ◽  
pp. 12833-12841 ◽  
Author(s):  
Daniel P. Tabor ◽  
Rafael Gómez-Bombarelli ◽  
Liuchuan Tong ◽  
Roy G. Gordon ◽  
Michael J. Aziz ◽  
...  
Keyword(s):  
Virtual Screening ◽  
High Throughput ◽  
Aqueous Media ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
Aqueous Flow ◽  
The Stability ◽  
Stability Limits ◽  
High Throughput Virtual Screening

The stability limits of quinones, molecules that show promise as redox-active electrolytes in aqueous flow batteries, are explored for a range of backbone and substituent combinations with high-throughput virtual screening.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

scholarly journals Tuning the Performance of Aqueous Organic Redox Flow Batteries from First Principles

2020 ◽  
Author(s):  
Junting Yu ◽  
Tianshou Zhao ◽  
Ding Pan
Keyword(s):  
Energy Storage ◽  
First Principles ◽  
High Performance ◽  
Large Scale ◽  
Electrical Energy ◽  
Ab Initio Molecular Dynamics ◽  
Redox Potentials ◽  
Redox Flow Batteries ◽  
Flow Batteries ◽  
Entropy Effects

<div>Aqueous organic redox flow batteries have many appealing properties in the application of large-scale energy storage. The large chemical tunability of organic electrolytes shows great potential to improve the performance of flow batteries. Computational studies at the quantum-mechanics level are very useful to guide experiments, but in previous studies explicit water interactions and thermodynamic effects were ignored. Here, we applied the computational electrochemistry method based on ab initio molecular dynamics to calculate redox potentials of quinones and their derivatives. The calculated results are in excellent agreement with experimental data. We mixed side chains to tune their reduction potentials, and found that solvation interactions and entropy effects play a significant role in side-chain engineering. Based on our calculations, we proposed several high-performance negative and positive electrolytes. Our first-principles study paves the way towards the development of large-scale and sustainable electrical energy storage.</div>

A subtractive approach to molecular engineering of dimethoxybenzene-based redox materials for non-aqueous flow batteries

2015 ◽  
Vol 3 (29) ◽  
pp. 14971-14976 ◽  
Author(s):  
Jinhua Huang ◽  
Liang Su ◽  
Jeffrey A. Kowalski ◽  
John L. Barton ◽  
Magali Ferrandon ◽  
...  
Keyword(s):  
High Capacity ◽  
Molecular Engineering ◽  
Active Materials ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
Aqueous Flow

The development of new high capacity redox active materials is key to realizing the potential of non-aqueous redox flow batteries (RFBs).

scholarly journals New insights into phenazine-based organic redox flow batteries by using high-throughput DFT modelling

2020 ◽  
Vol 4 (11) ◽  
pp. 5513-5521 ◽  
Author(s):  
Carlos de la Cruz ◽  
Antonio Molina ◽  
Nagaraj Patil ◽  
Edgar Ventosa ◽  
Rebeca Marcilla ◽  
...  
Keyword(s):  
Dft Calculations ◽  
High Throughput ◽  
Aqueous Media ◽  
Redox Potentials ◽  
Structure Property ◽  
Redox Flow Batteries ◽  
Structure Property Relationships ◽  
Flow Batteries ◽  
Dft Modelling ◽  
Interesting Structure

DFT calculations reveal interesting structure–property relationships of the redox potentials of phenazines in non-aqueous media.

scholarly journals Substituent Pattern Effects on the Redox Potentials of Quinone‐Based Active Materials for Aqueous Redox Flow Batteries

ChemSusChem ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5480-5488
Author(s):  
S. Schwan ◽  
D. Schröder ◽  
H. A. Wegner ◽  
J. Janek ◽  
D. Mollenhauer
Keyword(s):  
Redox Potentials ◽  
Active Materials ◽  
Redox Flow Batteries ◽  
Flow Batteries
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