Cyclohexanedione as the negative electrode reaction for aqueous organic redox flow batteries

Facile and efficient methods to prepare active electrodes for redox reactions of electrolyte ions are required to produce efficient and low-cost redox flow batteries (RFBs). Carbon-fiber electrodes are widely used in various types of RFBs and surface oxidation is commonly performed to enhance the redox reactions, although it is not necessarily efficient. Quite recently, a technique for nanoscale and uniform surface etching of the carbon fiber surface was developed and a significant enhancement of the negative electrode reaction of vanadium redox flow batteries was attained, although the enhancement was limited to the positive electrode reaction. In this study, we attempted to obtain an additional enhancement effect of metal-oxide nanoparticles without the need for further processing steps. A coating with carbonaceous thin films was obtained coating by sublimation, deposition, and pyrolysis of tin(II) phthalocyanine (SnPc) on a carbon fiber surface in a single heat-treatment step. The subsequent thermal oxidation concurrently achieved nanoscale surface etching and loading with SnO2 nanoparticles. The nanoscale-etched and SnO2-loaded surface was characterized by field-emission scanning electron microscopy (FESEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The activity for the vanadium ion redox reactions was evaluated by cyclic voltammetry (CV) to demonstrate the enhancement of both the positive and negative electrode reactions. A full cell test of the vanadium redox flow battery (VRFB) showed a significant decrease of the overpotential and a stable cycling performance. A facile and efficient technique based on the nanoscale processing of the carbon fiber surface was presented to substantially enhance the activity for the redox reactions in redox flow batteries.

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Bismuth Trioxide Modified Carbon Nanotubes as Negative Electrode Catalysts for all Vanadium Redox Flow Batteries

International Journal of Electrochemical Science ◽

10.20964/2020.08.34 ◽

2020 ◽

pp. 7733-7743

Author(s):

Youqun Chu ◽

Keyword(s):

Carbon Nanotubes ◽

Negative Electrode ◽

Bismuth Trioxide ◽

Redox Flow Batteries ◽

Flow Batteries ◽

Modified Carbon Nanotubes ◽

Vanadium Redox

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Electrochemical Studies on Alizarin Red S as Negolyte for Redox Flow Battery: a Preliminary Study

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.35.22764 ◽

2018 ◽

Vol 7 (4.35) ◽

pp. 375

Author(s):

C. Khor ◽

M. R. Mohamed ◽

C. K. Feng ◽

P. K. Leung

Keyword(s):

Diffusion Coefficient ◽

Negative Electrode ◽

Operating Conditions ◽

Alizarin Red S ◽

Fast Diffusion ◽

Redox Flow Battery ◽

Flow Battery ◽

Alizarin Red ◽

Redox Flow Batteries ◽

Flow Batteries

Redox flow battery (RFB) has received tremendous attention as energy storage system coupled with renewable energy sources. In this paper, a low-cost alizarin red S (ARS) organic dye is proposed to serve as the active material for the negative electrode reaction for organic redox flow batteries. Cyclic voltammetry has been conducted under a number of operating conditions to reveal the electrochemical performance of this molecule. The results suggest that ARS is highly reversible at low electrode potential (c.a. 0.082 V vs. standard hydrogen electrode), indicating that ARS is a promising negative electrode material for organic redox flow batteries. The diffusion coefficient of ARS is calculated in the range of 6.424 x 10-4 cm2 s-1, This has indicated fast diffusion rate and electrochemical kinetics for oxidation and reduction in higher concentration of ARS. It has been found out that the higher concentration of ARS in base electrolyte cause lowest diffusion coefficient due to solubility issue of ARS.

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Enhanced Performance of Zn/Br Flow Battery Using N-Methyl-N-Propylmorpholinium Bromide as Complexing Agent

International Journal of Molecular Sciences ◽

10.3390/ijms22179288 ◽

2021 ◽

Vol 22 (17) ◽

pp. 9288

Author(s):

Uxua Jiménez-Blasco ◽

Eduardo Moreno ◽

Maura Cólera ◽

Pilar Díaz-Carrasco ◽

José C. Arrebola ◽

...

Keyword(s):

Aqueous Electrolyte ◽

Negative Electrode ◽

Effective Area ◽

Complexing Agents ◽

Complexing Agent ◽

Metallic Zinc ◽

Quaternary Amine ◽

Promising Alternative ◽

Redox Flow Batteries ◽

Flow Batteries

Redox flow batteries (RFB) are one of the most interesting technologies in the field of energy storage, since they allow the decoupling of power and capacity. Zinc–bromine flow batteries (ZBFB) are a type of hybrid RFB, as the capacity depends on the effective area of the negative electrode (anode), on which metallic zinc is deposited during the charging process. Gaseous bromine is generated at the positive electrode (cathode) during the charging process, so the use of bromine complexing agents (BCA) is very important. These BCAs are quaternary amines capable of complexation with bromine and generating an organic phase, immiscible with the aqueous electrolyte. One of the most commonly used BCAs in RFB technology is 4-methylethylmorpholinium bromide (MEM-Br). In this work, an alternative quaternary amine 4-methylpropylmorpholinium bromide (MPM-Br) was studied. MPM-Br was integrated into the electrolyte, and 200 charge–discharge cycles were performed on the resulting ZBFBs. The obtained results were compared with those when MEM-Br was used, and it was observed that the electrolyte with MPM-Br displays a higher resistance in voltage and higher energy efficiency, making it a promising alternative to MEM-Br.

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