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Electrochemical hydrogen compression is a promising alternative to conventional mechanical compression due to low maintenance costs and high one-stage compression ratios. The typically employed planar systems, however, are intrinsically difficult to operate in high differential pressure environments. Tubular systems are inherently advantageous for high differential pressure systems but require innovative membrane electrode assembly development. This study unveils the first tubular EHC featuring a membrane electrode assembly supported by a stainless steel 3D-printed porous anode. The membrane electrode assembly for gas-phase electrochemistry is produced by spray coating the porous anode with Pt/C as the catalyst and joining the anode with a tubular catalyst-coated membrane. Electrochemical characterization demonstrates the functionality of the tubular EHC at current densities up to 60 mAcm − 2 with a cell potential of 200 mV under non-pressurized conditions. Moreover, a pressure difference of 2 bar is achieved at 60 mAcm − 2 within the first 60 min in continuous mode. By demonstrating the proof-of-principle for the first tubular EHC, this work paves the way for new research avenues in electrochemical process engineering, offering a broad spectrum of applications, from enhancing EHC technologies to advancing electrochemical CO 2 reduction. • Tubular membrane electrode assembly for electrochemical hydrogen compression. • Metal 3D-printed tubular electrode with tunable porosity. • Electrochemical characterization of tubular module. • A maximum hydrogen compression of 2 bar at current densities up to 60 mA/cm2. [Display omitted] [ABSTRACT FROM AUTHOR]

In situ techniques are essential to understanding the behavior of electrocatalysts under operating conditions. When employed, in situ synchrotron grazing-incidence X-ray diffraction (GI-XRD) can provide time-resolved structural information of materials formed at the electrode surface. In situ cells, however, often require epoxy resins to secure electrodes, do not enable electrolyte flow, or exhibit limited chemical compatibility, hindering the study of non-aqueous electrochemical systems. Here, a versatile electrochemical cell for air-free in situ synchrotron GI-XRD during non-aqueous Li-mediated electrochemical N2 reduction (Li-N2R) has been designed. This cell not only fulfills the stringent material requirements necessary to study this system but is also readily extendable to other electrochemical systems. Under conditions relevant to non-aqueous Li-N2R, the formation of Li metal, LiOH and Li2O as well as a peak consistent with the α-phase of Li3N was observed, thus demonstrating the functionality of this cell toward developing a mechanistic understanding of complicated electrochemical systems.

The industrial adoption of microbial electrosynthesis (MES) is hindered by high overpotentials deriving from low electrolyte conductivity and inefficient cell designs. In this study, a mixed microbial consortium originating from an anaerobic digester operated under saline conditions (∼13 g L−1 NaCl) was adapted for acetate production from bicarbonate in galvanostatic (0.25 mA cm−2) H-type cells at 5, 10, 15, or 20 g L−1 NaCl concentration. The acetogenic communities were successfully enriched only at 5 and 10 g L−1 NaCl, revealing an inhibitory threshold of about 6 g L−1 Na+. The enriched planktonic communities were then used as inoculum for 3D printed, three-chamber cells equipped with a gas diffusion biocathode. The cells were fed with CO2 gas and operated galvanostatically (0.25 or 1.00 mA cm−2). The highest production rate of 55.4 g m−2 d−1 (0.89 g L−1 d−1), with 82.4% Coulombic efficiency, was obtained at 5 g L−1 NaCl concentration and 1 mA cm−2 applied current, achieving an average acetate production of 44.7 kg MWh−1. Scanning electron microscopy and 16S rRNA sequencing analysis confirmed the formation of a cathodic biofilm dominated by Acetobacterium sp. Finally, three 3D printed cells were hydraulically connected in series to simulate an MES stack, achieving three-fold production rates than with the single cell at 0.25 mA cm−2. This confirms that three-chamber MES cells are an efficient and scalable technology for CO2 bio-electro recycling to acetate and that moderate saline conditions (5 g L−1 NaCl) can help reduce their power demand while preserving the activity of acetogens.

In situ techniques are essential to understanding the behavior of electrocatalysts under operating conditions. When employed, in situ synchrotron grazing-incidence X-ray diffraction (GI-XRD) can provide time-resolved structural information of materials formed at the electrode surface. In situ cells, however, often require epoxy resins to secure electrodes, do not enable electrolyte flow, or exhibit limited chemical compatibility, hindering the study of non-aqueous electrochemical systems. Here, a versatile electrochemical cell for air-free in situ synchrotron GI-XRD during non-aqueous Li-mediated electrochemical N2 reduction (Li-N2R) has been designed. This cell not only fulfills the stringent material requirements necessary to study this system but is also readily extendable to other electrochemical systems. Under conditions relevant to non-aqueous Li-N2R, the formation of Li metal, LiOH and Li2O as well as a peak consistent with the a-phase of Li3N was observed, thus demonstrating the functionality of this cell toward developing a mechanistic understanding of complicated electrochemical systems. [ABSTRACT FROM AUTHOR]

The influence of an active vibration isolator (AVI) and electrochemical cell design on natural convection was investigated. The natural convection of an electrolyte caused by external vibrations and acoustic sounds is reduced by both an AVI and an acoustic enclosure. Slow scan voltammetry with an AVI shows a reproducible and predictable diffusion-controlled current down to 0.4 mV/s. Reducing the distance between the working electrode and the glass wall also has a considerable effect on the voltammetric signal. [ABSTRACT FROM AUTHOR]

Electrocoagulation process (EC) has been the subject of several reviews in the last decade, and is still a very active area of research. Most published works deals with applications for treatment of drinking water and urban, industrial or agricultural wastewaters so as to enhance the simultaneous abatement of soluble and colloidal pollution. These also include contributions to theoretical understanding, electrode materials, operating conditions, reactor design and even techno-economic analysis. Even though, the numerous advantages reported in the literature, and the pros and cons of EC in comparison to alternative processes, its industrial application is not yet considered as an established wastewater technology because of the lack of systematic models for reactor scale-up. This paper presents a comprehensive review on its development and design. The most recent advances on EC reactor modeling are summarized with special emphasis on four major issues that still constitute the cornerstone of EC: the theoretical understanding of mechanisms governing pollution abatement, modeling approaches, CFD simulations, and techno-economic optimization. Finally, outlooks for future research and developments are suggested. [ABSTRACT FROM AUTHOR]

The industrial adoption of microbial electrosynthesis (MES) is hindered by high overpotentials deriving from low electrolyte conductivity and inefficient cell designs. In this study, a mixed microbial consortium originating from an anaerobic digester operated under saline conditions (∼13 g L -1 NaCl) was adapted for acetate production from bicarbonate in galvanostatic (0.25 mA cm -2 ) H-type cells at 5, 10, 15, or 20 g L -1 NaCl concentration. The acetogenic communities were successfully enriched only at 5 and 10 g L -1 NaCl, revealing an inhibitory threshold of about 6 g L -1 Na + . The enriched planktonic communities were then used as inoculum for 3D printed, three-chamber cells equipped with a gas diffusion biocathode. The cells were fed with CO 2 gas and operated galvanostatically (0.25 or 1.00 mA cm -2 ). The highest production rate of 55.4 g m -2  d -1 (0.89 g L -1  d -1 ), with 82.4% Coulombic efficiency, was obtained at 5 g L -1 NaCl concentration and 1 mA cm -2 applied current, achieving an average acetate production of 44.7 kg MWh -1 . Scanning electron microscopy and 16S rRNA sequencing analysis confirmed the formation of a cathodic biofilm dominated by Acetobacterium sp. Finally, three 3D printed cells were hydraulically connected in series to simulate an MES stack, achieving three-fold production rates than with the single cell at 0.25 mA cm -2 . This confirms that three-chamber MES cells are an efficient and scalable technology for CO 2 bio-electro recycling to acetate and that moderate saline conditions (5 g L -1 NaCl) can help reduce their power demand while preserving the activity of acetogens., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

A cell design to perform microscopic in-operando thermography across the interface anode — separator/electrolyte — cathode of a single lithium ion battery stack has been developed. A 3-electrode Swagelok® cell is adapted to enable the use of microscopic thermography during battery cycling. The developed measurement setup has been successfully tested using LiCoO 2 as cathode, LiPF 6 salt containing organic electrolyte and graphite as anode. The measurement results reveal differences in the heat generation of the individual components of the single battery stack. Furthermore, inhomogeneity in the electrodes can be detected and the heat transport on the micro scale can be observed. [ABSTRACT FROM AUTHOR]

High capacity sulfur electrodes are expected to be used in the next-generation of high energy density and low cost rechargeable lithium batteries. The positive sulfur electrode undergoes complex electrochemical reactions, which cause morphological changes of the composite electrode while cycling. In the course to deeper understand the failures of this rather complex, but promising technology, the operando technics are in the heart of the advanced characterizations. In this study, a new electrochemical cell was designed which allows, for the first time, the combination operando of multimodal X-ray characterizations: the absorption tomography to study the morphological evolution of electrodes, and the X-ray diffraction computed tomography to probe locally the structural modification of the crystalline active materials S 8 and Li 2 S. The combination of these two techniques simultaneously with the electrochemical cycling, allows the production of correlated 3D-maps of quantitative phase distributions and morphology in the electrode, with time resolution on the scale of battery kinetics. It was thus possible to show the heterogeneous behavior in the bulk of the electrode and to propose kinetics law. • New operando cell designed for coupling XRDCT and X-ray microtomography. • Correlated 3D-maps of phase distributions and morphology in the sulfur electrode. • Evidence of heterogeneous behavior in a 3D-electrode. [ABSTRACT FROM AUTHOR]

Lithium-based rechargeable batteries such as lithium-ion (Li-ion), lithium-sulfur (Li-S), and lithium-air (Li-air) cells typically consist of heterogenous porous electrodes. In recent years, there has been growing interest in the use of in-situ and operando micro-CT to capture their physical and chemical states in 3D. The development of in-situ electrochemical cells along with recent improvements in radiation sources have expanded the capabilities of micro-CT as a technique for longitudinal studies on operating mechanisms and degradation. In this paper, we present an overview of the capabilities of the current state of technology and demonstrate novel tomography cell designs we have developed to push the envelope of spatial and temporal resolution while maintaining good electrochemical performance. A bespoke PEEK in-situ cell was developed, which enabled imaging at a voxel resolution of ca. 230 nm and permitted the identification of sub-micron features within battery electrodes. To further improve the temporal resolution, future work will explore the use of iterative reconstruction algorithms, which require fewer angular projections for a comparable reconstruction. [ABSTRACT FROM AUTHOR]