Holey aligned electrodes through in-situ ZIF-8-assisted-etching for high-performance aqueous redox flow batteries

<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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