X‐Ray‐Computed Radiography and Tomography Study of Electrolyte Invasion and Distribution inside Pristine and Heat‐Treated Carbon Felts for Redox Flow Batteries

Gebhard, Marcus; Schnucklake, Maike; Hilger, André; Röhe, Maximilian; Osenberg, Markus; Krewer, Ulrike; Manke, Ingo; Roth, Christina

doi:10.1002/ente.201901214

Cited by 22 publications

(13 citation statements)

References 39 publications

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“…Redox flow batteries are a simple yet durable type of energy storage system that utilize reduction and oxidation reactions to store and release energy. − The electrodes used for these devices are made of a porous carbon structure that can undergo structural changes throughout compression and operation . The microstructure of the electrodes affects mass transport, pressure drop, and flow characteristics .…”

Section: Applications Of X-ray Ct To In Situ and Operando Studies In ...mentioning

confidence: 99%

“…The microstructure of the electrodes affects mass transport, pressure drop, and flow characteristics . The porous electrodes also have a large effect on the power density, overpotentials, and losses associated with battery performance, so it is important to characterize the electrode structure at the micron level through operando X-ray CT studies to understand how the electrodes function and see how to improve upon the electrode design. ,− These scans can show changes in the porosity, pore size distribution, and tortuosity within the porous electrodes as the operando cell operates. The flow field is another factor to consider for the overall cell design and functionality.…”

Section: Applications Of X-ray Ct To In Situ and Operando Studies In ...mentioning

confidence: 99%

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X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

Lang,

Kulkarni,

Foster

et al. 2023

Chem. Rev.

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Section: Applications Of X-ray Ct To In Situ and Operando Studies In ...mentioning

confidence: 99%

Section: Applications Of X-ray Ct To In Situ and Operando Studies In ...mentioning

confidence: 99%

X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

Lang,

Kulkarni,

Foster

et al. 2023

Chem. Rev.

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“…The regulation of fluidic hot spots by compression of the catalyst module induces stronger local turbulence in the flow path and significantly improves the reactor performance by >50% in the diffusion-limited regime, which has never been demonstrated in the SAC research . Direct observation of the velocity (and fluid distribution) inside the reactor can be achieved using an operando flow cell with X-ray transparent polyether ether ketone (PEEK) cover plates or thermal imaging with a quartz window . Taking the cue from redox flow batteries, it is generally beneficial to have narrow fluidic channels to promote mass-transfer kinetics .…”

Section: Reactor-level Understanding For Enhanced Productivitymentioning

confidence: 99%

Engineering Single Atom Catalysts for Flow Production: From Catalyst Design to Reactor Understandings

Chen

Liu

2022

Acc. Mater. Res.

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Conspectus In heterogeneous catalysis, the long-standing challenge is to achieve extremely high activity and chemoselectivity in liquid-phase organic transformations comparable to that of homogeneous or enzymatic processes. Single-atom catalysts (SACs) with atomically precise coordination are developed with the objectives to mimic the homogeneous pathways but face stability issues due to metal leaching or clustering. Additionally, the practical application of SACs in chemical production is hampered by the lack of standard preparation protocols and low conversion using laboratory batch reactors. This Account focuses on our recent studies in both catalyst design and reactor-level engineering for the flow synthesis of fine chemicals via SACs. At the catalyst and reaction level, we will discuss the intrinsic mechanism that controls reactivity and chemoselectivity in the SAC-catalyzed process and highlight examples where SACs outperform other catalytic approaches. Specifically, we reported the SAC-mediated preparation and late-stage functionalization of pharmaceutical drugs, including lonidamine, Tamiflu, cavosonstat, indomethacin, and many others by chemoselective transformations in a sequential or multicomponent manner. The ability of ultrahigh loading SACs in providing a multisite pathway for organic transformations involving two or more reactants is highlighted and contrasted with the single-site pathway in conventional SACs. Molecular-level understanding on the dynamic catalytic cycle obtained using operando X-ray absorption spectroscopies provides guidance for the design of more effective and leach resistant SACs. This also calls for the transformation of laboratory powder-based catalysts into industrially viable monolithic catalysts via formulation to further enhance the leach resistance. At the reactor level, we will highlight the importance of continuous-flow techniques in maximizing productivity and simplifying process transfer from laboratory to commercial production. Particularly, we discuss the use of fuel cell-type flow stacks for quantitative production of fine chemicals, including the synthesis of multifunctional anilines at a 5.8 g h–1 productivity using a Pt SAC module (3.2 mg Pt). Insight into multiscale reactor processes, for instance, the fluid diffusion kinetics, heat transfer, and influence of porosity and the gas–liquid–solid interface are provided by computational fluidic dynamics calculations as well as experimental techniques. In many cases, catalytic processes are more limited by mass diffusion than the intrinsic activity of the catalyst, calling for process optimization and engineering at the reactor level to enhance the productivity. Finally, we also identify technical barriers that need to be overcome in SAC research and offer our perspective on standardized and scalable protocols for mass production, the production cost analysis of typical SACs, high-throughput screening platforms, and novel flow reactor designs involving photochemical and electrochemical reactions for up-scaling chemic...

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“…A compromise was made between the size and volume of the cell to fit within the interests of the CT and flow cell. Gebhard et al [177] examined the porous electrode with a customized cell to study the invasive behavior of the electrolytes and their distribution. To enable the imaging of the electrodes, the material selection was made with the aim to minimize radiation absorption.…”

Section: Imaging Techniquesmentioning

confidence: 99%

In-Situ Tools Used in Vanadium Redox Flow Battery Research—Review

Ghimire¹,

Bhattarai²,

Lim

et al. 2021

Batteries

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Progress in renewable energy production has directed interest in advanced developments of energy storage systems. The all-vanadium redox flow battery (VRFB) is one of the attractive technologies for large scale energy storage due to its design versatility and scalability, longevity, good round-trip efficiencies, stable capacity and safety. Despite these advantages, the deployment of the vanadium battery has been limited due to vanadium and cell material costs, as well as supply issues. Improving stack power density can lower the cost per kW power output and therefore, intensive research and development is currently ongoing to improve cell performance by increasing electrode activity, reducing cell resistance, improving membrane selectivity and ionic conductivity, etc. In order to evaluate the cell performance arising from this intensive R&D, numerous physical, electrochemical and chemical techniques are employed, which are mostly carried out ex situ, particularly on cell characterizations. However, this approach is unable to provide in-depth insights into the changes within the cell during operation. Therefore, in situ diagnostic tools have been developed to acquire information relating to the design, operating parameters and cell materials during VRFB operation. This paper reviews in situ diagnostic tools used to realize an in-depth insight into the VRFBs. A systematic review of the previous research in the field is presented with the advantages and limitations of each technique being discussed, along with the recommendations to guide researchers to identify the most appropriate technique for specific investigations.

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X‐Ray‐Computed Radiography and Tomography Study of Electrolyte Invasion and Distribution inside Pristine and Heat‐Treated Carbon Felts for Redox Flow Batteries

Cited by 22 publications

References 39 publications

X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

X-ray Tomography Applied to Electrochemical Devices and Electrocatalysis

Engineering Single Atom Catalysts for Flow Production: From Catalyst Design to Reactor Understandings

In-Situ Tools Used in Vanadium Redox Flow Battery Research—Review

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