Metal anode instability, including dendrite growth, metal corrosion, and hetero-ions interference, occurring at the electrolyte/electrode interface of aqueous batteries, are among the most critical ...issues hindering their widespread use in energy storage. Herein, a universal strategy is proposed to overcome the anode instability issues by rationally designing alloyed materials, using Zn-M alloys as model systems (M = Mn and other transition metals). An in-situ optical visualization coupled with finite element analysis is utilized to mimic actual electrochemical environments analogous to the actual aqueous batteries and analyze the complex electrochemical behaviors. The Zn-Mn alloy anodes achieved stability over thousands of cycles even under harsh electrochemical conditions, including testing in seawater-based aqueous electrolytes and using a high current density of 80 mA cm
. The proposed design strategy and the in-situ visualization protocol for the observation of dendrite growth set up a new milestone in developing durable electrodes for aqueous batteries and beyond.
Electrochemistry studies charge transfer and related processes at various microscopic structures (atomic steps, islands, pits and kinks on electrodes), and mesoscopic materials (nanoparticles, ...nanowires, viruses, vesicles and cells) made by nature and humans, involving ions and molecules. The traditional approach measures averaged electrochemical quantities of a large ensemble of these individual entities, including the microstructures, mesoscopic materials, ions and molecules. There is a need to develop tools to study single entities because a real system is usually heterogeneous,
e.g.
, containing nanoparticles with different sizes and shapes. Even in the case of "homogeneous" molecules, they bind to different microscopic structures of an electrode, assume different conformations and fluctuate over time, leading to heterogeneous reactions. Here we highlight some emerging tools for studying single entity electrochemistry, discuss their strengths and weaknesses, and provide personal views on the need for tools with new capabilities for further advancing single entity electrochemistry.
We demonstrated an electrochemical microscopy technique based on the detection of variations in local electrochemical current from optical signals arising from surface plasmon resonance. It enables ...local electrochemical measurements (such as voltammetry and amperometry) with high spatial resolution and sensitivity, because the signal varies with current density rather than current. The imaging technique is noninvasive, scanning-free, and fast, and it constitutes a powerful tool for studying heterogeneous surface reactions and for analyzing trace chemicals.
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We report on label-free imaging, detection, and mass/size measurement of single viral particles in solution by high-resolution surface plasmon resonance microscopy. Diffraction of propagating plasmon ...waves along a metal surface by the viral particles creates images of the individual particles, which allow us to detect the binding of the viral particles to surfaces functionalized with and without antibodies. We show that the intensity of the particle image is related to the mass of the particle, from which we determine the mass and mass distribution of influenza viral particles with a mass detection limit of approximately 1 ag (or 0.2 fg/mm²). This work demonstrates a multiplexed method to measure the masses of individual viral particles and to study the binding activity of the viral particles.
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Aqueous zinc-ion batteries, in terms of integration with high safety, environmental benignity, and low cost, have attracted much attention for powering electronic devices and storage systems. ...However, the interface instability issues at the Zn anode caused by detrimental side reactions such as dendrite growth, hydrogen evolution, and metal corrosion at the solid (anode)/liquid (electrolyte) interface impede their practical applications in the fields requiring long-term performance persistence. Despite the rapid progress in suppressing the side reactions at the materials interface, the mechanism of ion storage and dendrite formation in practical aqueous zinc-ion batteries with dual-cation aqueous electrolytes is still unclear. Herein, we design an interface material consisting of forest-like three-dimensional zinc-copper alloy with engineered surfaces to explore the Zn plating/stripping mode in dual-cation electrolytes. The three-dimensional nanostructured surface of zinc-copper alloy is demonstrated to be in favor of effectively regulating the reaction kinetics of Zn plating/stripping processes. The developed interface materials suppress the dendrite growth on the anode surface towards high-performance persistent aqueous zinc-ion batteries in the aqueous electrolytes containing single and dual cations. This work remarkably enhances the fundamental understanding of dual-cation intercalation chemistry in aqueous electrochemical systems and provides a guide for exploring high-performance aqueous zinc-ion batteries and beyond.
Surface plasmon resonance (SPR) has become an indispensable tool for label-free detection and quantification of molecular binding. Traditionally, the principle of SPR biosensors is described with a ...stratified medium model, in which discrete molecules are approximated with a uniform thin film. With the recent technical advances, SPR can now detect extremely low coverage of molecules, which raises the question of the validity of the traditional model. Here, we present combined theoretical, numerical and experimental analysis of SPR detection principle by considering the discrete nature of the molecules (particles). Our results show that the stratified medium model can provide reasonable description of SPR biosensors for relatively high coverage and weakly scattering samples. However, interference between the SPR images of individual particles needs to be considered for high spatial resolution images and for strong scattering samples at certain incident angles of light.
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•Effect of Fe/Co/Ni on the ductility of TiAl was studied by theory and experiments.•Ni exists in the form of NiTi, which is detrimental to the ductility of TiAl.•Fe Co change electronic and elastic ...properties to improve ductility of TiAl.
The Ni atom is difficult to occupy the Ti or Al site in TiAl, it exists in the form of NiTi phase at the grain boundary of TiAl alloy, which is detrimental to the ductility of the TiAl alloy. The Fe and Co atoms preferentially occupy the Al sites and can improve the electronic structures and elastic properties of TiAl, leading to the improvement of the ductility of TiAl alloy. With the addition of 3at.% Fe and Co, the tested average fracture strain of TiAl alloy increases from 17.3% to 19.1% and 18.0%, respectively.
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The electrocatalytic properties of nanoparticles depend on their size, shape and composition. These properties are typically probed by measuring the total electrocatalytic reaction current of a large ...number of nanoparticles, but this approach is time-consuming and can only measure the average catalytic activity of the nanoparticles under study. However, the identification of new catalysts requires the ability to rapidly measure the properties of nanoparticles synthesized under various conditions and, ideally, to measure the electrocatalytic activity of individual nanoparticles. Here, we show that a plasmonic-based electrochemical current-imaging technique can simultaneously image and quantify the electrocatalytic reactions of an array of 1.6 × 10(5) platinum nanoparticles printed on an electrode surface, which could facilitate high-throughput screening of the catalytic activities of nanoparticles. We also show that the approach can be used to image the electrocatalytic reaction current and measure the cyclic voltammograms of single nanoparticles.
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•A super-sensitive carbon nanofiber aggregate (SSCNFA) sensor with 0.05% CNFs content has been developed.•The sensor's sensitivity is enhanced due to a well-defined conductive path ...between CNFs and steel mesh.•SSCNFA can detect forces as low as 0.28 N, making it suitable for stress/strain sensing and damage detection.•The sensor has a wide dynamic range, with any frequency from 1 Hz to 500 kHz available for various applications.
A carbon nanofiber aggregate of exceptional sensitivity is developed. Our approach involves the development and utilization of a novel nanobrush structure of carbon nanofiber within the mortar matrix. The high number of nanostructures in the nanobrush, particularly near the electrodes, results in a greater number of nanogaps, leading to a substantial improvement in sensitivity. We are able to detect forces as small as 1 N using this sensor. The carbon nanofiber brush (CNFB) provides a well-defined conductive path for the piezoresistive functioning of the super-sensitive carbon nanofiber aggregate (SSCNFA) with significantly reduced cost. The influence of scanning frequency in impedance is rigorously investigated with alternating current (AC) based on two methods. SSCNFAs are tested in uniaxial compression to determine the highly sensitive face of cube sensor. An SSCNFA (0.05 % CNFs, dense electrodes) and a CNFA (0.5 % CNFs, wide-spaced electrodes) were tested in a sweep-frequency test under parallel compression to compare the super-sensitive performance of the new sensor. The gauge factors at various frequencies were determined. The electrical impedance measured at various frequencies provides versatility to the SSCNFA for stress monitoring. Four fixed-frequency tests were conducted to determine the resolution under uniaxial compression and examine repeatability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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