X-ray computed micro-tomography of reticulated vitreous carbon

Current Opinion in Electrochemistry

2019

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151

Redox flow batteries continue to be developed for utility-scale energy storage applications. Progress on standardisation, safety and recycling regulations as well as financing has helped to improve their commercialisation. The technical progress of redox flow batteries has not considered adequately the significance of electrolyte flow velocity, mass transfer and plug flow reactor modelling, despite steps in the right direction. 3D simulations of fluid flow, pressure drop, current distribution and mechanical resistance using commercial software are becoming more common, but satisfactory validation by experiments is still unusual. The majority of research tends to report short term studies on small electrodes, often in poorly defined flow channels; long term evaluation of electrode and membrane durability on a pilot scale is needed. Digital imaging of electrode structure using X-ray computed tomography is increasingly being used. Much activity is directed to organic and non-aqueous systems. However, scale-up and high, sustained charge capacity using electrolytes of moderate cost which are environmentally acceptable to source, store, transport and handle require considerable attention. Recommendations for future work are discussed.

Section: Manufacturing Materials and Utility-scale Research Needsmentioning

confidence: 99%

Redox flow batteries for energy storage: their promise, achievements and challenges

Current Opinion in Electrochemistry

2019

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151

“…3 shows the analysis of bare Ti felt by CT, which afforded characteristics such as porosity and volumetric surface area. It must be stressed, however, that the calculated surface area depends on the resolution, thresholding method and processing algorithm [55]. For metals, only the porosity of a 3D printed Ti alloy [56], and the tortuosity of Ni foams [57] have been reported.…”

Section: Advanced Imaging Characterizationmentioning

confidence: 99%

Three-dimensional porous metal electrodes: Fabrication, characterisation and use

Current Opinion in Electrochemistry

2019

Diverse 3D porous metal electrodes, including meshes, foams and felts, are used in electrochemical flow reactors for a wide range of industrial applications, such as energy storage, electrosynthesis and degradation of pollutants. Recent work centres on the hierarchical decoration and coating of 3D electrodes with catalysts, although the study of their performance in a controlled and reproducible flow and mass transfer environment ought to receive more attention. New advances have considered metal nanofelts and nanomesh porous electrodes which show superior productivity. Opportunities are found in additive manufacturing, advanced structural characterization by e.g., X-ray computed tomography, and in 3D modelling of the hydrodynamic characteristics, current distribution and mass transfer coefficient.

“…The controlled electrodeposition of Sn-Cu alloys from methanesulphonic acid electrolytes on porous, 3D carbon supports has been demonstrated by Low et al 60 Figure 19(a) shows the surface of a coating on RVC, which comprises a network of interconnected pores and provides a rigid, high surface area substrate. [22][23][24] Figure 19(b) depicts a cross-section of the 4Sn46Cu50Bi alloy at the surface. Compressible carbon felts also were coated with the Sn-Cu alloy, as shown in Fig.…”

Section: Coatings and Surface Finishesmentioning

confidence: 99%

“…Examples are considered in the following section. Furthermore, the continued development of classical imaging tools, such as scanning and transmission plus atomic force microscopy, together with the introduction of newer techniques such as X‐ray computed tomography have done much to reveal the surface morphology of submicrometric structured surfaces and stimulate research in this area.…”

Section: Fabrication and Imaging Of Electrodesmentioning

confidence: 99%

Developments in electrode design: structure, decoration and applications of electrodes for electrochemical technology

J of Chemical Tech & Biotech

2018

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The diversity of cell geometries and their use for electrochemical processing and energy conversion are concisely reviewed, updating earlier treatments, with an emphasis on an engineering approach to electrode design. Electrode size varies from several cm2 in the laboratory to stacks containing hundreds of m2 at the industrial plant scale, and currents can range from nA at laboratory to many 100 kA in industry. Electrode materials include metals, conductive ceramics and polymers, as well as polymer–metal or ceramic–metal composites. Area, electrocatalytic activity and functionality can be tailored by selecting an appropriate support structure‐coating combination. The core structure of porous supports can be a foam, mesh or particulate bed, whereas the surface can be enhanced using numerous techniques. Inspiration for electrode design can come from multiple sources, including biomimetics and technology transfer. Important aspects of electrodes include manufacture, electrochemical activity, active area, the possibilities of 3D and nanostructured surfaces, decoration and functionalization, in addition to reasonable cost and adequate lifetime. The diversity of electrodes is illustrated by examples from the authors' laboratory in the fields of inorganic and organic synthesis, environmental remediation of wastewaters, surface finishing of materials and energy storage/conversion. A forward look is made to potential future developments in electrochemical technology. © 2018 Society of Chemical Industry