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1. Spatially Directed Functionalization by Co-electropolymerization of Two 3,4-ethylenedioxythiophene Derivatives on Microelectrodes within an Array

   https://doi.org/10.1149/1945-7111/abcb75  

   Jones, Benjamin J.; Korzeniewski, Carol; Franco, Jefferson H.; Minteer, Shelley D.; Fritsch, Ingrid (December 2020, Journal of The Electrochemical Society)

   Electrodeposited conductive copolymer films with predictable relative properties (quantities of functional groups for further modification and capacitance) are of interest in sensors, organic electronic materials and energy applications. Potentiodynamic copolymerization of films in aqueous solutions of two different thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl)methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), containing 0.02 M total monomer (0, 25, 34, 50, 66, 75, 100 mol%2), 0.05 M sodium dodecyl sulfate, and 0.1 M LiClO₄, on gold microelectrodes in an array was investigated. Decreasing monomer deposited (m)from 0 to 100 mol%2is attributed to a decreasing pH that inhibits electropolymerization. Molar ratios of1and2in the films, determined by micro-attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, tracks closely with the ratio in the deposition solutions. Capacitances measured from cyclic voltammetry in aqueous buffer and electron transfer of ferrocyanide at the films are unaffected by copolymer composition, except for the 100 mol%2case. Ratios of reverse-to-forward faradaic peak currents suggest that films with high content of1expand in the anodic form and contract in the cathodic form and vice versa for films with high content of2, where anions and cations dominate counterion transport from solution, respectively. 

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2. Electrodeposited thin-film Cu _x Sb anodes for Li-ion batteries: enhancement of cycle life via tuning of film composition and engineering of the film-substrate interface

   https://doi.org/10.1039/c8ta01798k  

   Schulze, Maxwell C.; Schulze, Roland K.; Prieto, Amy L. (January 2018, Journal of Materials Chemistry A)

   Electrodeposited Cu–Sb thin films on Cu and Ni substrates are investigated as alloy anodes for Li-ion batteries to elucidate the effects of both the film composition and substrate interactions on anode cycling stability and lifetime. Thin films of composition Cu x Sb (0 < x < 2) exhibit the longest cycle lifetimes nearest x = 1. Additionally, the Cu–Sb films exhibit shorter cycle lifetimes when electrodeposited onto Cu substrates when compared to equivalent films on Ni substrates. Ex situ characterization and differential capacity analysis of the anodes reveal that significant interdiffusion occurs during cycling between pure Sb films and Cu substrates. The great extent of interdiffusion results in mechanical weakening of the film–substrate interface that exacerbates film delamination and decreases cycle lifetimes of Cu–Sb films on Cu substrates regardless of the film's composition. The results presented here demonstrate that the composition of the anode alone is not the most important predictor of long term cycle stability; the composition coupled with the identity of the substrate is key. These interactions are critical to understand in the design of high capacity, large volume change materials fabricated without the need for additional binders. 

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3. Electrodeposition of Molybdenum from Water-in-Acetate Electrolytes

   https://doi.org/10.1149/1945-7111/ad59c8  

   Liu, Quanhong; Huang, Qiang (June 2024, Journal of The Electrochemical Society)

   This paper reports a systematic study on the electrodeposition of metallic molybdenum from water-in-salt electrolytes containing superhigh concentrations of acetate. Cyclic voltammetry and DC deposition were carried out on rotating disk electrodes with various concentrations of CH₃COOK and CH₃COONH₄to determine the effects of NH₄⁺and K⁺on Mo deposition. A comparison was performed between CH₃COOLi, CH₃COONa, and CH₃COOK to study the effects of different alkali metal cations. A synergistic effect was observed between K⁺and NH₄⁺, where Mo deposition rate is enhanced in the presence of both cations. However, such synergistic effect was not observed between NH₄⁺and other alkali cations. In addition, the impact of substrate on Mo deposition was also studied using Pt and Cu electrodes with different activity toward hydrogen evolution reaction. Electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the surface morphology, crystallographic structure, and metallic state of Mo in the electrodeposited films. 

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4. Combinatorial Growth of Vertically Aligned Nanocomposite Thin Films for Accelerated Exploration in Composition Variation

   https://doi.org/10.1002/smsc.202300049  

   Rutherford, Bethany X.; Zhang, Di; Quigley, Lizabeth; Barnard, James P.; Yang, Bo; Lu, Juanjuan; Kunwar, Sundar; Dou, Hongyi; Shen, Jianan; Chen, Aiping; et al (September 2023, Small Science)

   Combinatorial growth is capable of creating a compositional gradient for thin film materials and thus has been adopted to explore composition variation mostly for metallic alloy thin films and some dopant concentrations for ceramic thin films. This study uses a combinatorial pulsed laser deposition method to successfully fabricate two‐phase oxide–oxide vertically aligned nanocomposite (VAN) thin films of La_0.7Sr_0.3MnO₃(LSMO)‐NiO with variable composition across the film area. The LSMO‐NiO compositional gradient across the film alters the two‐phase morphology of the VAN through varying nanopillar size and density. Additionally, the magnetic anisotropy and magnetoresistance properties of the nanocomposite thin films increase with increasing NiO composition. This demonstration of a combinatorial method for VAN growth can increase the efficiency of nanocomposite thin film research by allowing all possible compositions of thin film materials to be explored in a single deposition. 

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5. Characterizing oxidation, thickness, and composition of metallic glass thin films with combined electron probe microanalysis and X-ray photoelectron spectroscopy

   https://doi.org/10.1016/j.apsusc.2024.160377  

   Muley, Sachin V; Nachlas, William O; Moy, Aurelien; Voyles, Paul M; Fournelle, John H (August 2024, Applied Surface Science)

   Metallic glass thin films (MGTFs) are a recently developed class of alloy coatings with potential applications ranging from biomedical devices to electrical components. Their tribological performance in service conditions is dictated by MGTF bulk composition but can be limited by the native oxide surface that inevitably forms upon exposure to atmosphere. Surface oxidation, thickness, and composition of ZrCuNiAl MGTFs were characterized using a combination of X-ray photoelectron microscopy (XPS) and electron probe microanalysis (EPMA). MGTF samples with nominal thicknesses of 50, 500, and 1500 nm were sputtered onto Si and SiN wafer substrates within a high vacuum deposition chamber and their amorphicity was confirmed by X-ray diffraction. XPS depth profiling identified the thin film composition and showed that the surface oxide was dominated by a mixed layer of mostly ZrO2, a little oxidized Al, and some metallic Zr. EPMA X-ray intensities were acquired as a function of beam energy to excite characteristic X-rays from different depths of the MGTFs and reconstructed using open-source thin film analysis software BadgerFilm, to determine the composition and thickness of sample layers. EPMA results constrain the composition to be Zr54Cu29Al10Ni7 within 0.7 at. % variation and total thicknesses to be 49, 470, and 1546 nm. Using the oxide composition identified from XPS depth profiling as an input for BadgerFilm analysis, EPMA results indicate the surface oxidation layer on each of the thin film samples was 6.5 ± 1.1 nm thick and uniform across a 0.25 mm region of the film. 

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