Direct visualization of reactant transport in forced convection electrochemical cells and its application to redox flow batteries

Rubio-García, Javier; Kucernak, Anthony; Charleson, Alexandra

doi:10.1016/j.elecom.2018.07.002

Cited by 13 publications

(4 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…presented a method based on electro‐chemiluminescent reactions to optically observe the mass transfer in liquid electrolytes. [ 137 ] The apparatus configuration is shown in Figure . The study used luminol as a probe molecule.…”

Section: Optical Microscopy Studies Of Redox Flow Batteriesmentioning

confidence: 99%

Seeing is Believing: In Situ/Operando Optical Microscopy for Probing Electrochemical Energy Systems

Chen

Zhang

Xuan

et al. 2020

Adv Materials Technologies

View full text Add to dashboard Cite

Understanding the mechanisms and fundamentals inside the EESs are critical to improve their performances by boosting the favorable processes and suppressing the detrimental ones. Various ex situ techniques have been used for studying EESs, which provide valuable spatial and temporal information. [6-8] Nevertheless, ex situ methods are limited by the time delay and potential impacts during the operation of removing samples from their initial environments to characterization locations. [9] The results might sometimes be missing or even misleading. This elicits the requirement for in situ/operando methods to conduct real-time observations on reactions and processes inside a system. In situ analytical techniques can provide more realistic information on the ongoing chemical and physical processes in an electrochemical cell. [10] Furthermore, correlating in situ information with electrochemical results obtained synchronously from the same device enables to build a direct cause-and-effect relationship, leading to authentic conclusions. [11] Remarkable progress has been made with advanced characterization techniques including optical, [12] X-ray, [13] electron microscopy, [14] neutron techniques. [15] The techniques work on very different principles. Optical microscopy is based on transmitting light to construct images for the samples. It has a wide effective characterization scales from centimeter to lower than micrometer. X-ray characterization techniques utilize electromagnetic radiation to magnify the samples. X-ray methods, including diffraction, absorption spectroscopy, photoelectron spectroscopy and X-ray microscopy, provide crucial information from mesoscale morphology to microscale crystal structure and elemental content of electrode materials. [16] Electron micro scopy probes the samples with electron beams. [17] The techniques based on neutron are quite similar as electron, and neutrons are preferable for analyses of light elements such as lithium ion (Li +). Also, Neutrons can go in more penetration depth with a weaker interaction with matter. [18] With the employment of these techniques, the knowledge of mechanisms of EESs has been significantly enhanced. On the other hand, in situ/operando experiments are restricted under certain circumstances, as they generally require special designs and modifications of the unit structures. Compared with other techniques, optical microscopy is preferable for in situ/operando studies considering the basic equipment needed, nonvacuum manipulation, easy access and operation, as well as its nondestructive nature. [19] However, inspections based on optical microscopy require access within the systems for transmitting light. This review discusses a range of in situ/operando techniques based on optical microscopy reported in literatures for studying electrochemical energy systems. Compared to other techniques (scanning probe microscopy, electron microscopy, X-ray microscopy), optical microscopy offers many advantages including the simplicity of the instrument and operation, co...

show abstract

Section: Optical Microscopy Studies Of Redox Flow Batteriesmentioning

confidence: 99%

Seeing is Believing: In Situ/Operando Optical Microscopy for Probing Electrochemical Energy Systems

Chen

Zhang

Xuan

et al. 2020

Adv Materials Technologies

View full text Add to dashboard Cite

show abstract

“…Various methods have been used to visualize processes occurring in electrochemical cells, including electron, X‐ray, and optical microscopy . To visualize the chemical boundary layer, fluorescence and electrogenerated luminescence methods have been reported . Visualization of mass transport phenomena in a redox flow battery has been reported by Charleson and co‐workers .…”

Section: Figurementioning

confidence: 99%

“…To visualize the chemical boundary layer, fluorescence and electrogenerated luminescence methods have been reported . Visualization of mass transport phenomena in a redox flow battery has been reported by Charleson and co‐workers . Using fluorescence microscopy with pH‐sensitive dyes, the evolution of the pH distribution can be studied in‐operando …”

Section: Figurementioning

confidence: 99%

In‐Operando Mapping of pH Distribution in Electrochemical Processes

et al. 2019

View full text Add to dashboard Cite

In aqueous electrochemical processes, the pH evolves spatially and temporally, and often dictates the process performance. Herein, a new method for the in‐operando monitoring of pH distribution in an electrochemical cell is demonstrated. A combination of pH‐sensitive fluorescent dyes, encompassing a wide pH range from ≈1.5 to 8.5, and rapid electrochemically coupled laser scanning confocal microscopy is used to observe pH changes in the cell. Using electrocoagulation as an example process, we show that the method provides new insights into the reaction mechanisms. The pH close to the aluminium electrode surface is influenced by the applied current density, hydrolysis of aluminium cations, and gas evolution. Through quantification of the pH at the anode, along with gas analysis, we find that hydrogen is evolved at the anode due to a non‐Faradaic chemical reaction. This leads to increased production of coagulant, which may open new routes to enhance the process performance. This method for in‐operando dynamic visualization of pH paves the way for studies of electrochemical processes, including other water treatment, electrosynthesis, and batteries.

show abstract

“…In an RFB-like system, electrolyte bypassing has been investigated by monitoring the mass transport with an electrochemiluminescent reaction of a luminol solution. The analysis showed that bypassing is possibly one important aspect for limiting mass transport [22]. In this context, carbon papers were mostly applied in RFBs.…”

Section: Introductionmentioning

confidence: 99%

Exploring Flow Characteristics in Vanadium Redox‐Flow Batteries: Optical Measurements and CFD Simulations

Prumbohm

Wehinger

2019

Chemie Ingenieur Technik

View full text Add to dashboard Cite

A thorough understanding of the flow characteristics of vanadium redox-flow batteries is essential for their improvement. With a combined approach of CFD simulations linked with optical measurements, the distribution in a carbon felt electrode of the vanadium electrolyte as well as of an alternative fluid substitute is compared and in all three dimensions analyzed leading to qualitatively consistent results. Yet, the experimentally observed partially inhomogeneous flow distribution is not predicted by the pseudo-homogeneous porous media CFD model.

show abstract

Direct visualization of reactant transport in forced convection electrochemical cells and its application to redox flow batteries

Cited by 13 publications

References 21 publications

Seeing is Believing: In Situ/Operando Optical Microscopy for Probing Electrochemical Energy Systems

Seeing is Believing: In Situ/Operando Optical Microscopy for Probing Electrochemical Energy Systems

In‐Operando Mapping of pH Distribution in Electrochemical Processes

Exploring Flow Characteristics in Vanadium Redox‐Flow Batteries: Optical Measurements and CFD Simulations

Contact Info

Product

Resources

About