bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Scanning Gel Electrochemical Microscopy: Towards Biological Applications?
Authors: Liu Liang , Brites Helu Mariela , Dang Ning , Echeveste Salazar Gustavo Adrian , Zammali Marouen , Etienne Mathieu , Walcarius Alain
Published: August 2024

Scanning electrochemical probe techniques have been developed in the last 30 years for measuring spatially localized electrochemistry at micro and nano scale. Here, we will present a recently developed tool, namely Scanning Gel Electrochemical Microscopy, for imaging the electrochemical reactivity of surfaces and patterning surfaces by local electrodeposition. The concept is based on a gel probe that is in soft contact with the sample, allowing electrochemical measurements to be spatially localized in the contact area with gel as electrolyte.1 The physical resolution, or the pixel size, can thus be tuned by pressing or pulling the probe after touching the sample.2 So far, two types of gel probes have been developed: Type I by electrodeposition of chitosan on micro-disk electrodes,1-3 and Type II by “electrodeposition + pulling” on sharpened metal wires.4 Local chronoamperometry, potentiometry and cyclic voltammetry have been carried out, either for imaging or for patterning (complex-shaped) surfaces.1-4

The gel has an advantage of localizing and immobilizing the electrolyte, which “frees” the sample from solution in scanning electrochemical microscopy (SECM) and reduces the wetting in scanning electrochemical cell microscopy (SECCM) as supported by quartz crystal microbalance (QCM) measurements in our recent work.5 Moreover, the excellent biocompatibility of the chitosan-based gel (which can easily immobilize drugs, proteins or bacteria) and the soft contact make SGECM a promising technique for biological applications. In this presentation, we will discuss about the feasibility of measuring different possible responses when a gel probe is in contact with a bio-entity (bacteria, bio-film, etc.) in-situ in its culture media: (1) Transport of redox species through the bio-entity, either from the gel to the culture media or the opposite way; (2) Production of redox mediators by the bio-entity that would be captured by the gel probe; (3) Physical and chemical response of the bio-entity induced by the gel probe. These possibilities will be examined by electrochemical modelling. The recent development on polyvinylalcohol-based gel probes will also be introduced. The work is partially supported by ANR-NRF project MEACT (ANR-20-CE09-0028).

References:

1. L. Liu, M. Etienne, A. Walcarius, Anal.
Chem., 2018, 90, 8889-8895.

2. N. Dang, M. Etienne, A. Walcarius, L. Liu, Anal. Chem., 2020,92, 6415-6422.

3. N. Dang, M. Etienne, A. Walcarius, L. Liu, Electrochem. Commun., 2018, 97, 64-67.

4. M. A. Brites Helú, L. Liu, Chem. Eng. J., 2021, 416, 129029.

5. G. A. Echeveste Salazar, M.A. Brites Helú, A. Walcarius, L. Liu, Electrochim. Acta,
2023, 437, 141455.

Figure 1
Covalently Immobilized Anthraquinone on Carbon and Its Use As a Proton-Exchange Counter Electrode in Impurity Sensitive Electrochemical Measurements
Authors: Williams Caroline Katherine , Papa Lopes Pietro Papa
Published: August 2024

The choice of counter electrode has emerged as an important topic in our search for non-platinum group metal (PGM) materials that can catalyze reactions that are important for fuel cells and electrolyzers such as oxygen reduction reaction (ORR), H2 evolution reaction (HER), and the CO2 reduction reaction. Recent investigations on the stability of Pt materials have revealed that significant dissolution occurs during O2 evolution, making the use of Pt as a counter electrode unsuitable for developing non-PGM materials for ORR and HER, in particular. That has led to increased use of carbon as the counter electrode, which can also oxidize at high voltages and generate partial oxidization compounds such as CO and other small organic molecules, which in turn, are detrimental to metal surfaces. Therefore, developing a stable counter electrode material is key for artifact-free electrocatalytic measurements. In this work, we will discuss the synthesis and application as a counter electrode of a proton-exchange anthraquinone-based reversible redox pair that was covalently grafted onto a high-purity (e.g. 99.99995%) carbon rod. The anthraquinone-grafted counter electrodes were evaluated in aqueous electrolytes using metal single crystals such as Pt(111) and Ir(111) surfaces as the working electrodes, given their extreme sensitivity to impurities in the electrochemical cell. Our results show that the counter electrode voltage is far more stable and centered around the proton-exchange process happening at the anthraquinone centers. This is in contrast to the wide-range voltage changes observed when using the un-grafted carbon rod. There were no differences in the single-crystal surface cyclic voltammetry profile, even after performing HER or OER, which typically causes the biggest swings in the counter electrode voltages. Lastly, there were no detectable amounts of grafted material leaching or exfoliated carbon, confirming that the use of a known redox pair such as from anthraquinone is an effective strategy to prevent artifacts in electrocatalysis research.
Square Wave Electrogravimetry Monitors Transient Submonolayer Adsorption of Redox-Active Molecules with a Precision of Less Than 1% of a Monolayer
Authors: Leppin Christian , Langhoff Arne , Johannsmann Diethelm
Published: August 2024

Square wave voltammetry on electrolytes containing the reversible redox pairs flavin adenine dinucleotide (FAD) and methyl viologen (MV) was complemented by a new form of acoustic microgravimetry. The analytes FAD and MV have promising applications in bacterial fuel cells and redox flow batteries. The instrument operates similarly to a quartz crystal microbalance with dissipation monitoring (EQCM-D). It reports shifts in resonance frequency and half bandwidth on several overtones. Compared to the existing instruments, the time resolution was improved by a factor of 40 down to 2.5 ms by multifrequency lockin amplification, which is important for the analysis of the transients in electrochemistry. The frequency noise after accumulation was reduced below 10 mHz ≙ 0.12 ng/cm2 ≙ 1.2 pm (assuming ρ = 1 g/cm3) by employing modulation and averaging. Square wave modulation of the electrode potential is superior to linear ramps (cyclic voltammetry) because it reduces the contribution of non-Faraday currents and, also, improves sensitivity. The shifts of frequency,Δf, and half bandwidth, ΔΓ, are in line with the Sauerbrey prediction (Δf/n
≈const. and ΔΓ/n < -Δf/nwith n the overtone order). Small deviations (Figure B and D) presumably are caused by the layer’s softness. The apparent shear modulus, G
app, of this layer is in the GPa range. The frequency difference, Δf/n|CT (Figure E), amounts to an apparent mass transfer rate. Plots of Δf/n|CT versus potential sometimes show curves similar to the electric current as observed for e. g. MV. For FAD, the results obtained depended on pH and the apparent mass transfer rates are much different from the current (Figure C and E). This difference is most likely caused by adsorbed molecules that are intermediates of the underlying two-electron process. The explanation is further corroborated by the response time of the QCM signals being much larger than the RC time of double layer recharging as determined with EIS. An interpretation in terms of adsorption/desorption is more plausible than an interpretation in terms of changed viscosity in the diffuse double layer.[1]

Caption: Currents and frequency shifts obtained on a solution containing FAD. Df/n|av evidences the preferred adsorption of the intermediate state (FADH).

References

[1] Leppin, Christian; Langhoff, Arne; Johannsmann, Diethelm. Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions. 2022, 94 (28), 10227–10233.

Figure 1
NiFe-Based Electrocatalysts for Electrochemical Reduction of Selenite
Authors: Ma Shengcun , Tong Wei
Published: August 2024

Selenite, a common oxyanion pollutant in water, poses a significant threat to human health due to its bioaccumulation through the food chain. This study explores the viability of direct electrochemical reduction as an effective method for selenite removal, with a particular focus on the affordable Ni-based electrocatalyst materials. Among several Ni-based electrocatalysts, NiFe emerges as a superior material, demonstrating excellent selenite removal performance (82.6%) and Faradaic efficiency (57.3%) compared to gold (52.7% and 31.4%, respectively), a benchmark electrocatalyst for selenite removal reported in literature. Notably, NiFe exhibits substantially lower energy consumption (5.1 kWh per kg selenite removal) than goal (9.0 kWh per kg selenite removal). Environmental conditions, including the selenite concentration, temperature, and the presence of other oxyanions, are systematically investigated. Negligible impacts from nitrate and sulfate are observed. Elevating temperature significantly enhances selenite removal, with no adverse impact on Faradaic efficiency. Electrochemical active surface area analysis, supported by SEM figures, confirms the stability of NiFe during the selenite removal process. This study establishes NiFe as a robust and cost-effective electrocatalyst for the direct electrochemical reduction of selenite, offering promising prospects for addressing selenite contamination in water.
Alternative Technique to RDE to Evaluate Photoelectrocatalysts for ORR
Authors: García Caballero Ariadna D , Diaz-Real Jesus Adrián
Published: August 2024

The scarcity of fuels due to the growing energy demand has encouraged research into topics such as energy conversion with materials that can take advantage of solar energy. Such situations have promote the emergence of various new materials to assist reactions of special interest such as oxygen reactions. (Oxygen Reduction Reaction, ORR and Oxygen Evolution Reaction, OER). Thus, numerous materials are emerging with the photoelectrocatalytic activity towards OER and ORR reactions. To evaluate the photo-assisted OER requires technical conditions that a rotating disk electrode (RDE) does not satisfy.

In this work we present an alternative technique to RDE by adapting a flow in a microfluidic platform to satisfy the limit current while it can be irradiated and thus evaluate the photoelectocatalysis of a semiconductor that has the characteristic of a photoelectrocatalyst.

To make the comparison, a glassy carbon electrode (GCE) was used using the Pt/C system in a three-electrode cell designed with a microfluidic channel where we found that the mass flow is comparable to rpm.
A Unified Multiscale Framework for Simulating Electrochemical Gas Evolving Reactions
Authors: Zhang Muhan , Li Weihong , Zhang Lenan
Published: August 2024

The presence of gas bubbles in electrochemical systems, such as water-splitting, significantly increases overpotential and diminishes energy efficiency. High-fidelity simulation holds significant promise to gain mechanistic understanding of bubble dynamics and guide high-performance electrolytic cell design. However, the extreme length scales involved into electrochemical gas evolving systems, from sub-nanometer dictated by the electrical double layer (EDL) to a few centimeters featured by the electrolytic cell, have posed a huge challenge to enable sufficient numerical accuracy and superior computational efficiency. As a result, state-of-the-art numerical approaches either can only simulate a nanoscale computational domain or neglect the electrochemical kinetics within the EDL, impeding an in-depth understanding of how bubbles could intervene with the electrochemical process.

In this work, we demonstrate a full-field simulation approach of electrochemical gas evolving reactions that can capture the electrochemical kinetics of the EDL in a centimeter-scale electrolytical cell with the presence of micro-to-millimeter scale bubbles. To resolve all characteristic length scales, the EDL is geometrically decoupled from the electrolytical cell but physically coupled with the bulk electrolyte and gas bubble through a quasi-1D treatment. As a result, the Nernst-Planck-Poisson-Boltzmann model can be rigorously solved in both the EDL and the rest of the electrolytical cell with highly affordable computational cost. Taking hydrogen evolution reaction as an example, we validated our approach by comparing with a variety of existing numerical and experimental results. For the first time, the impact of bubbles on the increase of overpotential observed in experiments can be quantitatively confirmed through numerical simulation. More notably, compared to state-of-the-art high-fidelity simulations, our approach exhibits a remarkable computational efficiency, which reduced the computational time by a factor of 100,000. This work provides a viable solution to simulate electrochemical gas evolving reactions with highly desirable numerical accuracy and unprecedented computational efficiency, which can serve as an effective tool to understand bubble dynamics and guide the design of next-generation electrolytical cells.
(Invited) Computational Design and Analysis of Novel Battery Electrolytes Driven by the Grotthuss Mechanism
Authors: Tuckerman Mark E
Published: August 2024

Candidate systems for next-generation electrolyte materials, such as deep eutectic solvents and ionic liquids, often suffer from high viscosities, which suppresses rates of charge transport and limits their performance characteristics. A strategy for circumventing this problem is to leverage the structural or Grotthuss mechanism of proton transport through hydrogen-bond networks, which can exhibit high proton diffusion rates even when rates of vehicular charge transport are poor. In this talk, I will describe a project aimed at leveraging computational design and simulation approaches, in combination with experimental synthesis and characterization, to develop a novel class of battery electrolytes based on the structural/Grotthuss diffusion mechanism. The workflow involves identification of a suitable proton-carrier liquid, a proton source, and a redox-active species capable of undergoing proton-coupled electron transfer (PCET) reactions. I will discuss the computational methods, which involve a combination of machine learning and first-principles simulation techniques, candidate chemical species for each of the components, first simulation and experimental protocols for combining these components into a high-performance electrolyte, preliminary results, and next steps in the evolution of the project. This work will serve to illustrate both the power of modern computational approaches in the design of electrochemical systems but also to broaden the perspective on what constitutes a “breakthrough” electrolyte.

Figure 1
Deep Learning Assisted High Resolution Microscopy Image Processing for Phase Segmentation in Functional Composite Materials
Authors: Raghavendran Ganesh , Zhang Minghao , Meng Shirley
Published: August 2024

In the domain of battery research, the processing of high-resolution microscopy images is a challenging task, as it involves dealing with complex images and requires a prior understanding of the components involved. The utilization of deep learning methodologies for image analysis has attracted considerable interest in recent years, with multiple investigations employing such techniques for image segmentation and analysis within the realm of battery research. However, the automated analysis of high-resolution microscopy images for detecting phases and components in composite materials is still an underexplored area.

The presentation discusses the formulation of a sophisticated deep learning-assisted workflow tailored for the meticulous processing of high throughput, high-resolution microscopy images to detect, map and analyze the evolution of periodic components from a stack of high-resolution Transmission Electron Microscopy (TEM) image. The developed methodology employs deep learning techniques and utilizes Fast Fourier Transform (FFT) patterns extracted from TEM images to analyze feature positions and ascertain periodic components. The approach incorporates innovative strategies to process high-resolution images, capitalizing on the symmetry within FFT patterns to enhance model performance. This methodology streamlines the detection and mapping of components while the intensity profiles derived from the frames provide valuable insights into the evolution of periodic components within the sample during the imaging period.

High-resolution images obtained through a beam damage analysis investigation of lithium fluoride (LiF), a prevalent constituent within the solid-electrolyte interphase (SEI) of cycled lithium metal anodes, were employed to assess the program's scalability and robustness. The study elucidated decomposition products and their spatial distribution. Furthermore, the intensity profile of periodic components detected across multiple frames aided in evaluating the beam damage mechanism of the LiF component.

Our research has resulted in an open-source Python GUI program that the research community can freely access and experiment with.

Figure 1
(Invited) A Molecular Understanding of (Interfacial) Ion Solvation, and Its Implications for Electrochemistry
Authors: Cox Stephen James
Published: August 2024

Ions in solution play a central role in most electrochemical systems. Theoretical approaches rooted in continuum models, such as Debye-Hückel theory or the Born solvation model, provide the basis for much of our understanding about processes that involve dissolved ions. Despite the remarkable success of these relatively simple theories, their (drastic) assumptions can sometimes lead to a qualitatively incorrect description of the underlying chemical physics. Here, we will overview recent work from molecular simulations that casts light on the molecular details of both equilibrium and nonequilibrium processes in solution. Implications for relating the details of microscopic relaxation processes to experimental observables such as impedance and capacitance will also be discussed.
(Invited) First Principles Treatments of Heterogeneous Electrocatalysis – Reactivity Trends and Electrocatalyst Structure
Authors: Morankar Ankita , Deshpande Siddharth , Deshmukh Gaurav , Ghanekar Pushkar , Zeng Zhenhua , Greeley Jeffrey
Published: August 2024

Advances in the theoretical understanding of electrochemical systems have, over the past decade, led to growing use of periodic Density Functional Theory studies to treat a surprisingly large ensemble of electrocatalytic reactions, ranging from carbon dioxide electroreduction to oxygen evolution. Many such studies have employed simplified models of the electrochemical environment to determine reactivity trends across a broad space of catalytic materials, while other efforts have focused on developing detailed descriptions of electrochemical phenomena, such as the structure of electrochemical double layers, on model catalyst structures. An emerging challenge is to combine these approaches to ultimately enable theoretical design of electrocatalysts for reactions of significantly expanded chemical and materials complexity.

In this talk, I will begin by discussing how we have applied strategies from computational heterogeneous catalysis to design enhanced electrocatalysts for the classic oxygen reduction reaction. In such treatments, we have effected highly detailed analyses of the catalyst surface structure and have employed machine learning-based methods to describe interactions between the various ORR reaction intermediates that are present at significant surface coverages. I will then explore challenges in obtaining more detailed descriptions of the electrocatalytic reaction environment, including the structure of catalysts with solid/solid interfaces, the distribution of charges in electrochemical double layers, and the structure and entropy of solvents near the electrocatalyst surface. I will conclude with some perspectives on how these complexities may be incorporated into traditional computational catalyst screening approaches to identify improved materials for more complex electrocatalytic systems.
Physics-Based Impedance Model for Understanding Proton Transport in PEM Fuel Cells
Authors: Ince Alper Can , Kort-Kamp Wilton , Liyanage Wipula Priya Rasika , Spendelow Jacob S. , Pasaogullari Ugur , Borup Rod L. , Komini Babu Siddharth
Published: August 2024

The electrochemical impedance spectroscopy (EIS) diagnostics using H2/N2 operation condition developed for fuel cell is useful tools to estimate the catalyst layer (CL) proton resistance. Currently, the resistance is estimated by fitting the measured EIS data to an equivalent circuit model. However, it is challenging to correctly determine the transmission line circuit and accurately estimate the proton resistance [1]. Moreover, the capacitive and resistance elements in the transmission line model are assumed similar throughout the CL even if there is nonhomogeneous distribution of ionomer. To understand the EIS response in CL, we present a physics-based model. Utilizing the model, we are able to investigate the H2/N2 cell impedance response under various operating conditions. The continuum scale model will be combined with agglomerate scale model to provide a detail study of the electrode parameters like ionomer loading and ionomer coverage The hybrid theoretical model allows us to study the effect of nonhomogeneous CL and its corresponding EIS response.

Acknowledgement

This research is supported by U.S. Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office, through the Million Mile Fuel Cell Truck Consortium (M2FCT).

References:

[1] Malevich, D., Jayasankar, B. R., Halliop, E., Pharoah, J. G., Peppley, B. A., & Karan, K. (2012). On the determination of PEM fuel cell catalyst layer resistance from impedance measurement in H2/N2 cells. Journal of the Electrochemical Society, 159(12), F888.

[2] Liu, Y., Murphy, M. W., Baker, D. R., Gu, W., Ji, C., Jorne, J., & Gasteiger, H. A. (2009). Proton conduction and oxygen reduction kinetics in PEM fuel cell cathodes: effects of ionomer-to-carbon ratio and relative humidity. Journal of The Electrochemical Society, 156(8), B970.
In-Situ Liquid-Electrochemical X-Ray and Electron Microscopy for Multi-Modal Energy Materials Characterization
Authors: Parkin Calvin , Mefford Tyler , Lim Jongwoo , Yoon Aram , Serra-Maia Rui , Kumar Pawan , Chee See Wee , Chueh William C. , Alsem Daan Hein , Salmon Norman , Stach Eric A.
Published: August 2024

In-situ liquid cell electron and x-ray microscopy have enabled dynamic studies of electrochemical reactions in energy materials and revealed relationships between the performance, structure, and chemical composition of these material systems. Such fundamental relationships are critical to improving the performance of batteries, catalysts, and other energy materials. Growing research interest in energy materials systems has accelerated the development of in-situ liquid-electrochemical microscopy techniques into mature and robust characterization workflows using novel and versatile scientific hardware.

Multiple characterization techniques or in-situ processing steps are often required to fully understand the mechanisms governing the behavior of energy materials for all relevant length scales and environmental conditions. A multi-modal workflow combining in-situ liquid-electrochemical transmission electron, X-ray synchrotron and scanning electron microscopy methods is presented. The breadth of research applications is discussed, including the study of chemical dynamics and structural changes to micron-scale LixFePO4 battery particles during lithium-ion insertion/extraction, electrocatalytic behavior of β-Co(OH)2 platelet particles, and electrochemical oxidation of copper nanoparticles under reductive electrolytic conditions. New insights into these materials systems provided by these experiments will directly inform the development of predictive models for material performance and guide improvement of material design and synthesis.

New scientific hardware and method development has been critical to in-situ nano-scale liquid cell microscopy and spectroscopy of electrochemical systems. Therefore, best-practice hardware and method design and development for these in-situ liquid-electrochemical microscopy experiments are also discussed. The connections between potentiostat, holder, and on-chip leads must be carefully considered with respect to different ground potentials, and the incorporation of real bulk-scale reference electrodes in this hardware has yielded quantitatively higher fidelity data with less degradation from further electrochemical cycling. Heating the sample or illuminating with light during in-situ electrochemical data collection has begun to further expand the range of environmental conditions that can be incorporated into experiments.
(Invited) Bragg Coherent Diffraction Imaging Studies of Composition Distribution and Strain in Catalytic Alloy Nanoparticles
Authors: Kawaguchi Tomoya
Published: August 2024

Compositional distribution, strain, and defects in alloy nanoparticles significantly affect the catalytic properties for a wide range of applications such as gas reforming, fuel cells, electrolysis, etc. while various alloy compositions of nanoparticles have been investigated to improve performance and reduce the amount of precious metals used. It was reported that the composition distribution of the alloy particles, expectedly homogeneous in the whole particle, changed dynamically depending on the operating environment, resulting in altering the catalytic activity [1]. Furthermore, defects such as dislocations, grain boundaries, and elastic strain of the crystalline lattice also significantly affect catalytic properties. Since these factors dynamically change and evolve under operating environments, in situ measurements are essential to reveal these factors and ultimately to exploit them to enhance the catalytic properties.

Bragg coherent diffraction imaging (BCDI) is a lens-less imaging method that measures speckle patterns near Bragg diffraction from a crystalline sample and reconstructs the 3D particle images. Since Bragg diffraction is inherently sensitive to displacements of the crystal lattice, BCDI yields the displacement field within the sample as well as the electron density, i.e., the “shape” of the particle. This displacement field information further allows us to evaluate strain distribution, dislocations, and composition distribution in the particle. BCDI is also advantageous for in situ measurements because the 3D image can be obtained by rotating the sample by only a few degrees, which eases the geometrical constraint of an electrochemical cell for the measurement. This is in contrast to conventional 3D imaging techniques such as X-ray CT, which usually requires 180 degrees of sample rotation.

Furthermore, it is expected that the measurement capabilities of BCDI will be rapidly advanced by upgrading synchrotron radiation facilities such as APS-U, which delivers high-flux coherent X-rays. This should expand the applications of BCDI to wider electrochemical materials.

In this presentation, we will briefly overview the principle of BCDI followed by specific examples of in situ measurements of catalytic alloy particles [2-4] conducted at 34-ID-C at Advanced Photon Source.

[1] F. Tao et al., Science 322, 932 (2008).

[2] T. Kawaguchi et al., Phys. Rev. Lett. 123, 246001 (2019).

[3] T. Kawaguchi et al., Nano Lett. 21, 5945 (2021).

[4] D. Sheyfer, R. G. Mariano, T. Kawaguchi, et al., Nano Lett. 23, 1 (2023).
High-Density, Low-Tortuosity Sulfur Electrodes for High Energy Lithium–Sulfur Batteries
Authors: Shi Lili , Xiao Jie , Liu Jun , Lu Dongping
Published: August 2024

Lithium–sulfur (Li–S) batteries have attracted significant attention due to their promising theoretical energy and cost-effectiveness.[1] While recently studies have predominantly focused on increasing sulfur mass loading and utilization rate for high specific energy, there remains a noticeable gap in addressing the intrinsic challenge of improving volumetric energy density.[2] This challenge arises as many Li-S investigations rely on highly porous electrodes.[3] Here, we employ a shear-rolling approach to prepare free-standing electrodes characterized by high density (porosity<15%), low tortuosity, and substantial S content (>70%). The incorporation of a vascular-like porous network, facilitated by a pore soft template, plays a pivotal role in achieving high sulfur utilization (>1000 mAh g-1) in high-loading electrodes (>4 mg cm-2) under lean electrolyte condition (E/S 4 mL g-1). This approach results in an extraordinarily high volumetric energy density (668 Wh L-1 of dry cell) when applied to practical Li–S pouch cells. Our study underscores that realizing high volumetric energy in Li–S cell can be achieved by rationalizing the dense electrode architecture. Furthermore, the shear-rolling approach holds broad applicability for fabricating high-energy electrodes using porous or nanoparticle materials with desirable structures. Details of the progress will be discussed at the conference.

References

[1] Y. Cao, M. Li, J. Lu, J. Liu, K. Amine, Nat Nanotechnol
2019,
14, 200-207.

[2] S. Dorfler, H. Althues, P. Hartel, T. Abendroth, B. Schumm, S. Kaskel, Joule
2020,
4, 539-554.

[3] L. L. Shi, S. M. Bak, Z. Shadike, C. Q. Wang, C. J. Niu, P. Northrup, H. K. Lee, A. Y. Baranovskiy, C. S. Anderson, J. Qin, S. Feng, X. D. Ren, D. Y. Liu, X. Q. Yang, F. Gao, D. P. Lu, J. Xiao, J. Liu, Energy & Environmental Science
2020,
13, 3620-3632.
Understanding the Mechanical Behavior of Sulfide Solid Electrolyte Membranes for Practical Applications in All-Solid-State Batteries
Authors: Kim Mokwon , Hwang Seung-Sik , Ku Junhwan , Lee Yong-Gun
Published: August 2024

All-solid-state batteries (ASSBs) hold great promise as next-generation energy storage systems due to their enhanced stability and high energy density compared to traditional lithium-ion batteries. This improvement stems from the use of a solid electrolyte (SE) instead of a highly volatile liquid electrolyte and the incorporation of a lithium metal anode. In general, sulfide-based SSBs require adequate pressurization conditions to establish an intimate interface between the solid particles, ensuring a continuous electron/ion conduction path. At the cell level, maintaining external stack pressure during operation is crucial to preserve conformal solid-solid contact. Furthermore, when scaling up, fabrication pressure should be carefully considered to enhance electrode densification without causing damage. In particular, the fabrication of thin, robust, and scalable SE membranes faces practical challenges due to a limited amount of polymeric binder and the low intrinsic ductility of SEs after densification. Understanding the mechanical behavior of these SE membranes is essential to ensure their structural stability during manufacturing.

In this study, we systematically examined the mechanical properties of SE and SE membranes. The deformability of various types of sulfide SEs was assessed using a powder compaction test, departing from the commonly used indentation method. The yield pressure, which indicates the deformability of the SE powder, is influenced by the composition and synthesis conditions of the SEs. The stress-strain behaviors of the SE membranes were obtained through tensile and flexural tests for both as-prepared and pressed samples, respectively. The tensile and bending behaviors of the SE membranes strongly depend on the combination of the SE and polymeric binder. The utilization of a ductile SE and a rubbery polymer binder can enhance the flexibility and ductility of the membrane, leading to increased densification degree and low interfacial resistance even under lower fabrication pressure. The details of cell configuration, fabrication procedure, and the resulting performances of the cell will be discussed in this talk.
Improving Room Temperature Performance of All-Solid-State Polymer Batteries through Cell Activation
Authors: Xu Hongliang , Shi Lili , Wu Jing , Xiao Jie , Liu Jun , Lu Dongping
Published: August 2024

Solid polymer electrolytes (SPE) are gaining increasing attention for use in all-solid-state lithium batteries (ASSLB) due to their enhanced safety and simplified processing.[1] However, their conventional operation requires elevated temperatures.[2, 3] Here, we propose a straightforward hot-press activation method to facilitate cell operation at room temperature (r.t., 30 °C) for SPE-based ASSLB. This activation method induces grain amorphization, leading to a substantial reduction in grain boundary resistance within the SPE and achieving a fourfold increase in r.t. ionic conductivity. Furthermore, by decoupling Li-ion transport processes, the activation significantly diminishes the electrode-electrolyte interfacial resistances for both the cathode and anode, thereby enhancing kinetics and overall cell performance at r.t.. Through the application of an optimized activation procedure, all-solid-state LiFeO4 (LFP)|SPE|Li cells exhibit noteworthy performance enhancements, demonstrating both high specific capacity and stable cycling at r.t.

References

Mauger, A., et al., Building Better Batteries in the Solid State: A Review. Materials, 2019. 12(23).

Chen, R.J., et al., The pursuit of solid-state electrolytes for lithium batteries: from comprehensive insight to emerging horizons. Materials Horizons, 2016. 3(6): p. 487-516.

Mindemark, J., et al., Beyond PEO—Alternative host materials for Li + -conducting solid polymer electrolytes. Progress in Polymer Science, 2018. 81: p. 114-143.
(Invited) Solid/Electrolyte Interface Under Confinement in Divalent Water-in-Salt Electrolytes
Authors: Berlinger Sarah A. , Kuepers Verena , Dudenas Peter J , Schinski Devin , Flagg Lucas Q , Lamberty Zachary , McCloskey Bryan D. , Winter Martin , Frechette Joelle
Published: August 2024

Concentrated aqueous electrolytes (water-in-salt electrolytes, WiSEs) have gained increasing attention in the last few years because they display much wider electrochemical stability windows (upwards of 3V) than the thermodynamic limit of water (1.23V), making them exciting candidates for a variety of electrochemical systems including aqueous batteries. Importantly, it is the ions directly at the electrode/electrolyte interface that are key to explaining this unexpected reactivity. The electrode/electrolyte interface is classically thought of as the electrical double layer (EDL), or the ion arrangement at an interface that builds up to neutralize the surface potential. WiSEs present very different EDL structures than do classical dilute electrolytes. However, most work has focused on monovalent WiSEs, primarily motivated by Li-battery applications using lithium bis(trifluoromethylsulphonyl)imide (LiTFSI).

In this work, we aim to understand how divalent ions within the WiSE regime alter both the short-range and long-range signatures of the EDL under confinement. For most of the above applications, reactions occur within the pore-space of a porous electrode, which exhibit confined, overlapping EDLs. Therefore, we use confinement as a tool to probe both the short-range layering structure (<10 nm) and electrostatic decay length (~10-100 nm) away from a charged interface with Surface Forces Apparatus (SFA) measurements.

Using WiSEs comprising LiTFSI, Zn(TFSI)2, and mixtures of the two salts, we first establish the bulk structure of these electrolytes using Wide Angle X-Ray Scattering and Raman Spectroscopy, which reveal that the anion and cation are closely associated in all electrolytes, regardless of cation valency. Additionally, clusters of ions are formed in all electrolytes, however, the clusters are suppressed with increasing divalent ion fraction. Under confinement, SFA results demonstrate that the thickness of the adsorbed layer of ions at a solid/electrolyte interface grows with increasing divalent ion fraction. Multiple interfacial layers are formed following this adlayer, and these layers seem dependent on anion size, rather than cation. Importantly, all electrolytes exhibit very long electrostatic decay lengths that are insensitive to valency. This work contributes significant fundamental understanding regarding the structure and charge-neutralization mechanism in this class of electrolytes both in the bulk and under confinement at an interface.
(Digital Presentation) Sorting of Circulating Tumor Cells Based on Phenotypic Separation in Using Magnetic Nanoparticle Labels
Authors: Ebrahimi Sina , Shamloo Amir
Published: August 2024

Representing a practical criterion for sorting captured circulating tumor cells (CTCs) based on the cancer progression stage is a new approach that recently received traction. High-throughput, rapid, and cost-effective microfluidic systems that allow for high-efficiency separation and continuous inertial focusing are needed. The goal of the present study is to design of such systems via computational modeling and experimental tests. We propose a new microfluidic device that uses magnetic nanoparticles to label surface biomarkers on CTCs to isolate, focus and sort CTCs based on their cancer progression stage. By eliminating sheath flow interference that may result in harming cell survival, the proposed microchip can successfully determine the progression of cancer by arranging cells in one step. Additionally, the proposed device allows for rapid, efficient separation of the blood cells (RBCs and WBCs) and CTCs in the shortest length of the channel.
Opto- Electrochemical Detection of Waterborne Bacteria Using Bi-Functional Magnetic Nanoparticle Conjugates and Nile Red
Authors: Gunasekaran Dharanivasan , Eini Eran
Published: August 2024

Detection of microbial contamination in water is imperative to ensure water quality. We have developed an opto- electrochemical sensor for the detection of E. coli using bi-functional magnetic nanoparticle (MNP) conjugates and Nile Red (NR). The bi-functional MNP conjugates were prepared by terminal-specific conjugation of anti-E. coli IgG antibody and the electroactive marker ferrocene. The bi-functional MNP conjugate possesses both E. coli-specific binding and electroactive properties, which were studied in detail. The conjugation efficiency of ferrocene and IgG antibodies with amine-functionalized MNPs was investigated. Square-wave voltammetry enabled the detection of E. coli concentrations ranging from 101–107 cells/mL in a dose-dependent manner, as ferrocene-specific current signals were inversely dependent on E. coli concentrations, completely suppressed at concentrations higher than 107 cells/mL. MNP bioconjugate captured E.coli was also detected by fluorescence methods using NR staining which can bind with both membrane and cytoplasmic lipids. This MNP bioconjugate captured NR stained E.coli emits high intensity fluorescence with maximum wavelength at 635 nm when excitation with optimum wavelength at 559 nm and it appeared in deep red to golden –yellow color in fluorescence microscopic analysis. Fluorescence intensity has a direct relationship with concentrations of E.coli cells. The developed opto-electrochemical method is highly sensitive (10 cells/mL) and, coupled to magnetic separation, provides specific signals within 1h. Overall, the bi-functional conjugates serve as ideal candidates for opto-electrochemical detection of waterborne bacteria. This approach can be applied for the detection of other bacteria and viruses.

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Exploring the Gas-Sensing Mechanism of a WO3 Nanowires-Based Sensor for Ethanol Detection by Near-Ambient Pressure XPS
Authors: Vorochta Michael , Piliai Lesia , Dinhová Thu Ngan , Janata Martin , Hubalek Jaromir , Vrnata Martin , Matolínová Iva
Published: August 2024

The WO3 nanowires (NWs), fabricated on a commercial Al2O3-based sensor platform, underwent near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) analysis during ethanol detection. Our findings revealed challenges that may appear in utilizing NAP-XPS studies for studying a real gas sensor in operando conditions. Through NAP-XPS analysis, we explored the gas-sensing mechanisms of pristine and Pt-decorated WO3 NWs for ethanol sensing at different temperatures, demonstrating a combination of several mechanisms commonly observed in metal-oxide chemiresistors. For ethanol sensing, the primary driving force for the sensor's macroscopic electrical response at low temperatures was the adsorption of ethanol molecules. Conversely, at high temperatures, it involved the adsorption of ethoxy groups along with the reducing effect of ethanol on the WO3 surface. It is shown that the surface oxygen vacancies play a crucial role in the ethanol sensing mechanism of WO3 NWs-based gas sensors.

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Sustainable Synthesis of MIL-53(Al)-Cys Based Chemosensor for the Fluoro-Chromogenic Detection of Copper
Authors: Sharma Saloni , Kaur Gurjeet , Nayak Manoj Kumar , Deep Akash
Published: August 2024

Copper is the third most abundant heavy metal in the environment important for human survival. However, in excess it can have deleterious effects on aquatic as well as terrestrial beings. The detection of Cu2+ has huge significance in food safety and environment monitoring. The conventional detection methods are costly and complex. Therefore, we have designed a waste derived material for Cu2+ determination in complex samples. Our work is based on the eco-friendly synthesis of waste derived Al-MOF with remarkable properties grafted with L-Cysteine to develop the novel MIL-53(Al)-Cys sensor. The formation of the sensing probe was verified by various characterization techniques including FE-SEM, HR-TEM, PXRD, FTIR, UV-Vis and Photoluminescence spectroscopies. The developed waste-derived probe showed multifunctional properties with the visual and fluorescent detection of Cu2+ ions with high sensitivity and fast response time. The proposed waste-derived fluoro-chromogenic sensor exhibited a “turn of” detection response mechanism with a visual color change only the presence of Cu2+ ions. The results showed reproducible, selective and stable response with a LOD of 0.2 ng/mL, which is lower than the permissible levels. Therefore, the observed results highlight the potential of developed waste-derived MIL-53(Al)-Cys chemosensor as a promising platform in water remediation applications.
Antimicrobial Peptide-Based Sensor for the Electrochemical Detection of Methicillin-Resistant Staphylococcus Aureus
Authors: Liyanage Madhuka Malshani , Lai Rebecca
Published: August 2024

Methicillin-resistant Staphylococcus aureus (MRSA) is a gram-positive bacterium that colonizes on the skin and nasal track of humans, which can lead to serious illnesses such as skin and soft tissue infections, pneumonia, and septicemia.MRSA is resistant to an entire class of antibiotics called beta-lactams, including penicillin, amoxicillin, and oxacillin, making it more difficult to treat. Culture based methods and molecular based methods like PCR are currently being used for the detection of MRSA, but these methods possess the drawbacks of being slow and expensive, respectively. Thus, we focused on developing a reagentless, cost-effective, near real-time detection method for intact MRSA cells.

Antimicrobial peptides (AMPs) possess the ability to interact with bacterial cells by inhibiting their growth or by lysing them.However, this initial interaction between the cationic AMPs and the negatively charged bacterial cells can be used for the detection of pathogens like MRSA. Here, we used a MRSA-specific antimicrobial peptide, DP7, to fabricate an electrochemical peptide-based (E-PB) sensor. The DP7 probe was further modified with a methylene blue redox label and an alkanethiol chain which allows for the formation of a thiol-gold self-assembled monolayer. The sensor surface was passivated with both 6-mercapto-1-hexanol and a thiolated tetra-thymine sequence to prevent surface fouling. Electrochemical detection of MRSA was accomplished using alternating current voltammetry. Control experiments were performed using two gram-positive bacteria, Bacillus subtilis and Staphylococcus epidermidis, and two gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa. The DP7 sensor responded to MRSA in a concentration-dependent manner and was proven to be selective for MRSA over the other four microbes. Specifically, the % signal suppression obtained for MRSA was much larger when compared to those obtained for the other microbes. The same behavior was observed in pure buffer and 5% synthetic wound fluid. In addition, the detection time was relatively short, with signal saturation in less than 60 min. Overall, the DP7 sensor has demonstrated to possess attributes similar to other E-PB sensors. It has the potential to be developed as a rapid, reliable, and cost-effective diagnostic tool for MRSA, which will be useful in preventing the spread of the pathogen in the community. Furthermore, this sensing platform is versatile and can be redesigned for detection of other pathogenic bacteria.
Two-Dimensional (2D) Layered Metal–Organic Framework (MOF) Composites as an Electrochemical Sensor for Nitrofurans
Authors: Hsieh Yi-Ting
Published: August 2024

A two dimensional layer iron metal–organic framework (MOF), [Fe (bipy)(C4O4)(H2O)2]×3H2O (where bipy = 4,4’-bipyridine、 C4O4
2- (squarate) = dianion of squric acid) has been successfully synthesized. Hydrothermal synthesis was employed to incorporate these Fe-MOFs into reduced graphene oxide (rGO) nanosheets, forming Fe-MOF/rGO composites. SEM, TEM, XRD, XPS, and contact angle measurements were employed to analyze the composites. TEM studies revealed that the rod-shaped Fe-MOFs were uniformly dispersed on the rGO sheets. Incorporating Fe-MOF into rGO resulted in enhanced performance, which can be attributed to the composites' large surface area, chemical stability, and high electrical conductivity. The Fe-MOF/rGO modified electrodes exhibited significantly improved response signals for the electrochemical sensing of nitrofurazone, showcasing a lower detection limit. The sensor also demonstrated reproducible and stable anti-interference properties. To elucidate the mechanism behind the enhanced sensing performance, grand canonical Monte Carlo (GCMC) calculations were conducted. These calculations indicated that the interface between Fe-MOF and rGO effectively absorbed an increased number of NFZ molecules. These findings underscore the substantial improvement in the electrochemical performance of Fe-MOF/rGO composites, positioning them as promising materials for practical applications in nitrofurazone sensing.