POM Anolyte for All‐anion Redox Flow Batteries with High Capacity Retention and Coulombic Efficiency at Mild pH

Aqueous redox flow batteries (ARFBs) are a promising technology for large-scale energy storage. Developing high-capacity and long-cycle negolyte materials is one of major challenges for practical ARFBs. Inorganic polysulfide is promising for ARFBs owing to its low cost and high solubility. However, it suffers from severe crossover resulting in low coulombic efficiency and limited lifespan. Organosulfides are more resistant to crossover than polysulfides owing to their bulky structures, but they suffer from slow reaction kinetics. Herein, we report a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. The thiolate denoted as 2-hydroxyethyl disulfide+potassium polysulfide (HEDS+K2S2) shows reduced crossover rate than K2S2, faster reaction kinetics than HEDS, and longer lifespan than both HEDS and K2S2. The 1.5 M HEDS+1.5 M K2S2 static cell demonstrated 96 Ah L-1negolyte over 100 and 200 cycles with a high coulombic efficiency of 99.2% and 99.6% at 15 and 25 mA cm-2, respectively. The 0.5 M HEDS+0.5 M K2S2 flow cell delivered a stable and high capacity of 30.7 Ah L-1negolyte over 400 cycles (691 h) at 20 mA cm-2. This study presents an effective strategy to enable low-crossover and fast-kinetics sulfur-based negolytes for advanced ARFBs.

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Composite Polybenzimidazole Membrane with High Capacity Retention for Vanadium Redox Flow Batteries

Molecules ◽

10.3390/molecules26061679 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1679

Author(s):

Jacobus C. Duburg ◽

Kobra Azizi ◽

Søren Primdahl ◽

Hans Aage Hjuler ◽

Elena Zanzola ◽

...

Keyword(s):

Energy Storage ◽

Composite Membrane ◽

High Capacity ◽

High Energy ◽

Electricity Production ◽

Capacity Retention ◽

Redox Flow Batteries ◽

Flow Batteries ◽

Storage Technologies ◽

Capacity Drop

Currently, energy storage technologies are becoming essential in the transition of replacing fossil fuels with more renewable electricity production means. Among storage technologies, redox flow batteries (RFBs) can represent a valid option due to their unique characteristic of decoupling energy storage from power output. To push RFBs further into the market, it is essential to include low-cost materials such as new generation membranes with low ohmic resistance, high transport selectivity, and long durability. This work proposes a composite membrane for vanadium RFBs and a method of preparation. The membrane was prepared starting from two polymers, meta-polybenzimidazole (6 mm) and porous polypropylene (30 μm), through a gluing approach by hot-pressing. In a vanadium RFB, the composite membrane exhibited a high energy efficiency (~84%) and discharge capacity (~90%) with a 99% capacity retention over 90 cycles at 120 mA∙cm−2, exceeding commercial Nafion® NR212 (~82% efficiency, capacity drop from 90% to 40%) and Fumasep® FAP-450 (~76% efficiency, capacity drop from 80 to 65%).

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A Self-Trapping, Bipolar Viologen Bromide Electrolyte for Aqueous Redox Flow Batteries

10.26434/chemrxiv.12443654.v1 ◽

2020 ◽

Author(s):

wenda wu ◽

Jian Luo ◽

Fang Wang ◽

Bing Yuan ◽

Tianbiao Liu

Keyword(s):

Redox Flow Battery ◽

Capacity Retention ◽

Redox Flow Batteries ◽

Redox Electrolyte ◽

Charge Process ◽

Self Trapping ◽

Flow Batteries ◽

Total Capacity ◽

Neutral Conditions ◽

Low Solubility

Aqueous organic redox flow batteries (AORFBs) have become increasing attractive for scalable energy storage. However, it remains challenging to develop high voltage, powerful AORFBs because of the lack of catholytes with high redox potential. Herein, we report methyl viologen dibromide ([MV]Br2) as a facile self-trapping, bipolar redox electrolyte material for pH neutral redox flow battery applications. The formation of the [MV](Br3)2 complex was computationally predicted and experimentally confirmed. The low solubility [MV](Br3)2 complex in the catholyte during the battery charge process not only mitigates the crossover of charged tribromide species (Br3-) and addresses the toxicity concern of volatile bromine simultaneously. A 1.53 V bipolar MV/Br AORFB delivered outstanding battery performance at pH neutral conditions, specifically, 100% total capacity retention, 133 mW/cm2 power density, and 60% energy efficiency at 40 mA/cm2.

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

Journal of Materials Chemistry A ◽

10.1039/c5ta02380g ◽

2015 ◽

Vol 3 (29) ◽

pp. 14971-14976 ◽

Cited By ~ 66

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).

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A biomimetic high-capacity phenazine-based anolyte for aqueous organic redox flow batteries

Nature Energy ◽

10.1038/s41560-018-0167-3 ◽

2018 ◽

Vol 3 (6) ◽

pp. 508-514 ◽

Cited By ~ 112

Author(s):

Aaron Hollas ◽

Xiaoliang Wei ◽

Vijayakumar Murugesan ◽

Zimin Nie ◽

Bin Li ◽

...

Keyword(s):

High Capacity ◽

Redox Flow Batteries ◽

Flow Batteries

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Nitrogen-Doped Carbon Spheres-Decorated Graphite Felt as a High-Performance Electrode for Fe Based Redox Flow Batteries

10.21203/rs.3.rs-177033/v1 ◽

2021 ◽

Author(s):

Anarghya Dinesh ◽

Anantha Mylarapattana Shankaranarayana ◽

Santosh Mysore Srid ◽

Narendra Kumar Muniswamy ◽

Krishna Venkatesh ◽

...

Keyword(s):

High Performance ◽

Coulombic Efficiency ◽

Electrochemical Techniques ◽

Single Step ◽

Carbon Spheres ◽

Active Nitrogen ◽

Graphite Felt ◽

Redox Flow Batteries ◽

Flow Batteries ◽

Carbon Catalysts

Abstract In this paper, the performance of Fe based redox flow batteries (IRFBs) was dramatically improved by coating N-doped carbon spheres (NDCS) on the graphite felt electrodes. NDCS was synthesized by the single-step hydrothermal method using dextrose and ammonia as a precursor and coated over a graphite felt electrode by electrostatic spraying. The weight of NDCS required for the modification of the electrode to achieve the effective performance of the battery was studied using electrochemical techniques. Cyclic voltammetry (CV) and potentiodynamic polarization study was used to evaluate the kinetic reversibility and linear polarization resistance offered by the electrode towards electrolyte. The characterizing features of the NDCS, untreated graphite felt (UGF) electrode, and optimized modified graphite felt (MGF) electrode were analyzed using SEM, EDAX, XRD, and Raman spectroscopy. The charge-discharge studies were performed for the 132 cm2 IRFB using a 2 mg/cm2 MGF electrode as a positive electrode by varying the current densities from 20 to 60 mA/cm2. The cell resulted in an average coulombic efficiency (CE) of 93%, voltaic efficiency (VE) of 72%, and energy efficiency (EE) of 68% for 15 cycles at the current density of 30 mA/cm2. The improvement in the performance of the IRFB is due to the presence of electrochemically active nitrogen-bearing carbon catalysts. In this paper, the pioneering effort has been made to improve the efficiency of the IRFB with an active area of 132 cm2 using glycine as the ligand.

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