Evaluation of the catalytic effect of non-noble bismuth on the lead half-cell reaction for lead-based redox flow batteries

Redox flow batteries (RFBs) are a relatively new generation of electrochemical devices suitable for large-scale energy storage applications. The separation between the electrolyte storage tanks and the electrochemical cell in RFBs simplifies the battery scale-up and facilitates the energy/power ratio tuning. Among the different types of RFBs investigated, those based on zinc and cerium are very attractive due to the large negative and positive electrode potentials in an aqueous media. Thus, zinc-cerium RFBs are capable of providing one of the highest cell voltages (~ 2.4 V) among flow [1]. To date, Zn-Ce RFBs have primarily been investigated galvanostatically to determine their charge, voltage and energy efficiencies and attempts have been made to suppress the rate of the hydrogen evolution side reaction [2,3]. In order to further optimize the performance of these batteries and to elucidate the future pathways to enhance their efficiency, the sources of voltage loss in the battery during discharge must be identified and the role of the positive and negative half-cells in the voltage loss determined. Toward this goal, we have conducted in situ polarization and EIS experiments on a full-cell Zn-Ce RFB with reference electrodes inserted in the system. At low and intermediate current densities, the main contributor to the voltage loss during discharge is the kinetic overpotential of the negative Zn/Zn2+ half-cell. On the other hand, at high current densities, mass transfer limitations at the positive Ce3+/Ce4+ half-cell cause a large potential drop in the system. From in situ kinetic studies, we have measured an exchange current density of ~ 7.4*10−3 A cm−2 for Zn oxidation and ~ 24.2*10−3 A cm−2 for Ce4+ reduction, which supports the findings from battery operation that the kinetics of the negative electrode reaction is slow compared to that of the positive electrode at low-to-intermediate current densities. The use of an alternative mixed methanesulfonate-chloride negative electrolyte to reduce the kinetic overpotential of the negative half-cell reaction and the influence of the flow rate on the mass-transfer rate of the positive half-cell reaction have also been investigated and will be discussed in this presentation.

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Chloride ions as an electrolyte additive for high performance vanadium redox flow batteries

Applied Energy ◽

10.1016/j.apenergy.2021.116690 ◽

2021 ◽

Vol 289 ◽

pp. 116690

Author(s):

Z.H. Zhang ◽

L. Wei ◽

M.C. Wu ◽

B.F. Bai ◽

T.S. Zhao

Keyword(s):

High Performance ◽

Chloride Ions ◽

Electrolyte Additive ◽

Redox Flow Batteries ◽

Flow Batteries ◽

Vanadium Redox

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Imide-Based Multielectron Anolytes as High-Performance Materials in Nonaqueous Redox Flow Batteries

ACS Applied Energy Materials ◽

10.1021/acsaem.1c01490 ◽

2021 ◽

Author(s):

Nicolas Daub ◽

René A. J. Janssen ◽

Koen H. Hendriks

Keyword(s):

High Performance ◽

Redox Flow Batteries ◽

Flow Batteries

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

10.26434/chemrxiv.12956960.v2 ◽

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>

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Recent progress in zinc-based redox flow batteries: a review

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac4182 ◽

2021 ◽

Author(s):

Guixiang Wang ◽

Haitao Zou ◽

Xiaobo Zhu ◽

Mei Ding ◽

Chuankun Jia

Keyword(s):

High Performance ◽

Large Scale ◽

Electrode Materials ◽

Low Cost ◽

Ion Selectivity ◽

Commercial Application ◽

Environmental Friendliness ◽

Membrane Materials ◽

Redox Flow Batteries ◽

Flow Batteries

Abstract Zinc-based redox flow batteries (ZRFBs) have been considered as ones of the most promising large-scale energy storage technologies owing to their low cost, high safety, and environmental friendliness. However, their commercial application is still hindered by a few key problems. First, the hydrogen evolution and zinc dendrite formation cause poor cycling life, of which needs to ameliorated or overcome by finding suitable anolytes. Second, the stability and energy density of catholytes are unsatisfactory due to oxidation, corrosion, and low electrolyte concentration. Meanwhile, highly catalytic electrode materials remain to be explored and the ion selectivity and cost efficiency of membrane materials demands further improvement. In this review, we summarize different types of ZRFBs according to their electrolyte environments including ZRFBs using neutral, acidic, and alkaline electrolytes, then highlight the advances of key materials including electrode and membrane materials for ZRFBs, and finally discuss the challenges and perspectives for the future development of high-performance ZRFBs.

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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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