Electrocatalysis at Electrodes for VanadiumRedox Flow Batteries

Flow batteries (also: redox batteries or redox flow batteries RFB) are briefly introduced as systems for conversion and storage of electrical energy into chemical energy and back. Their place in the wide range of systems and processes for energy conversion and storage is outlined. Acceleration of electrochemical charge transfer for vanadium-based redox systems desired for improved performance efficiency of these systems is reviewed in detail; relevant data pertaining to other redox systems are added when possibly meriting attention. An attempt is made to separate effects simply caused by enlarged electrochemically active surface area and true (specific) electrocatalytic activity. Because this requires proper definition of the experimental setup and careful examination of experimental results, electrochemical methods employed in the reviewed studies are described first.

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Facile Fabrication of Double-Layered Electrodes for a Self-Powered Energy Conversion and Storage System

Nanomaterials ◽

10.3390/nano10122380 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2380

Author(s):

Seungju Jo ◽

Nagabandi Jayababu ◽

Daewon Kim

Keyword(s):

Energy Conversion ◽

Surface Area ◽

Active Surface ◽

Triboelectric Nanogenerator ◽

Active Surface Area ◽

Electrochemical Performances ◽

Energy Conversion And Storage ◽

Facile Fabrication ◽

Self Powered ◽

And Storage

An aluminum double-layered electrode (DE-Al) was successfully employed as two electrodes in a symmetrical supercapacitor (double-layered electrode symmetric SC (DE-SC)) and as a positive layer of a triboelectric nanogenerator (DE-TENG) with the aim of energy conversion and storage using a selfsame structured, self-powered flexible device. A facile water-assisted oxidation (WAO) process and metal sputtering after the WAO process can allow the electrodes to greatly improve the active surface area and the conductivity, leading to the enhancement of the electrochemical performances of a supercapacitor (SC). Particularly, this double-layered structure fabrication process is extremely less time-consuming and cost-effective. The electrochemical test of the proposed DE-Al was systematically conducted by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS), along with the in-depth characterizations of the surface. From these studies, the DE-Al offers exceptional electrochemical properties compared with other structures, which were utilized as the electrodes in the polyvinyl alcohol/phosphoric acid (PVA/H3PO4) gel electrolyte. The improved performance apparently evidenced from the electrochemical tests of fabricated SC resulted from the enhanced electrical conductivity and large active surface area. The specific capacitance and cycle-life stability of the DE-SC were investigated by using a GCD analysis. Additionally, the EIS curves before and after stability test (for 3500 cycles) were obtained to prove the long-term endurance of DE-SC. A vertical contact and the separation mode of the TENG were also fabricated by using the same DE-Al as a positive layer and polydimethylsiloxane (PDMS) as a negative layer. Finally, the fabricated SC and TENG were successfully combined using a bridge rectifier to convert and store the mechanical energy as electrical energy. This simple design and facile fabrication of a double-layered-electrode-based structure is promising for the development of an energy conversion and storage device.

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Next-Generation Electrochemical Energy Conversion and Storage Based on Three-Dimensional Nanostructures with Improved Performance: Insights and Perspectives

10.1007/978-981-16-5371-1_4 ◽

2021 ◽

pp. 31-41

Author(s):

Shubhadip Paul

Keyword(s):

Energy Conversion ◽

Three Dimensional ◽

Next Generation ◽

Electrochemical Energy Conversion ◽

Energy Conversion And Storage ◽

Improved Performance ◽

And Storage ◽

Electrochemical Energy

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A review on recent developments of anion exchange membranes for fuel cells and redox flow batteries

RSC Advances ◽

10.1039/c5ra04741b ◽

2015 ◽

Vol 5 (47) ◽

pp. 37206-37230 ◽

Cited By ~ 106

Author(s):

Sandip Maurya ◽

Sung-Hee Shin ◽

Yekyung Kim ◽

Seung-Hyeon Moon

Keyword(s):

Fuel Cells ◽

Anion Exchange ◽

Storage Systems ◽

Anion Exchange Membranes ◽

Future Perspectives ◽

Redox Flow Batteries ◽

Flow Batteries ◽

Energy Conversion And Storage ◽

Recent Developments ◽

And Storage

This review covers recent advancements and future perspectives of AEMs for energy conversion and storage systems such as fuel cells and redox flow batteries.

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Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

Journal of Electroceramics ◽

10.1007/s10832-013-9872-2 ◽

2014 ◽

Vol 32 (1) ◽

pp. 3-27 ◽

Cited By ~ 26

Author(s):

J. G. Swallow ◽

W. H. Woodford ◽

Y. Chen ◽

Q. Lu ◽

J. J. Kim ◽

...

Keyword(s):

Energy Conversion ◽

Electrical Energy ◽

Energy Conversion And Storage ◽

Conductive Ceramics ◽

And Storage

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Practical use of polymer brushes in sustainable energy applications: interfacial nanoarchitectonics for high-efficiency devices

Chemical Society Reviews ◽

10.1039/c8cs00705e ◽

2019 ◽

Vol 48 (3) ◽

pp. 814-849 ◽

Cited By ~ 41

Author(s):

Juan M. Giussi ◽

M. Lorena Cortez ◽

Waldemar A. Marmisollé ◽

Omar Azzaroni

Keyword(s):

Energy Conversion ◽

Polymer Brushes ◽

High Efficiency ◽

Sustainable Energy ◽

Storage Devices ◽

Energy Applications ◽

Energy Conversion And Storage ◽

Improved Performance ◽

New Perspective ◽

And Storage

Polymer brushes provide a new perspective from which to consider the development of energy conversion and storage devices with improved performance and efficiency.

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Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

10.26434/chemrxiv.7770338.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Kailun Yang ◽

Recep Kas ◽

Wilson A. Smith

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Catalyst Layer ◽

Active Surface ◽

Active Surface Area ◽

High Concentration ◽

Copper Electrodes ◽

Surface Enhanced ◽

Local Current

This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO2 electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO2 electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO2 electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer.

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