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Title: In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry

Abstract

The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurements and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO 2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO 2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Institute of Standards and Technology (NIST)
OSTI Identifier:
1372235
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Synchrotron Radiation (Online); Journal Volume: 24; Journal Issue: 4
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Young, Matthias J., Bedford, Nicholas M., Jiang, Naisheng, Lin, Deqing, and Dai, Liming. In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry. United States: N. p., 2017. Web. doi:10.1107/S1600577517006282.
Young, Matthias J., Bedford, Nicholas M., Jiang, Naisheng, Lin, Deqing, & Dai, Liming. In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry. United States. doi:10.1107/S1600577517006282.
Young, Matthias J., Bedford, Nicholas M., Jiang, Naisheng, Lin, Deqing, and Dai, Liming. 2017. "In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry". United States. doi:10.1107/S1600577517006282.
@article{osti_1372235,
title = {In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry},
author = {Young, Matthias J. and Bedford, Nicholas M. and Jiang, Naisheng and Lin, Deqing and Dai, Liming},
abstractNote = {The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurements and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.},
doi = {10.1107/S1600577517006282},
journal = {Journal of Synchrotron Radiation (Online)},
number = 4,
volume = 24,
place = {United States},
year = 2017,
month = 5
}
  • High intensity synchrotron x-ray radiation has increased the feasibility of studying the solid--liquid interface [ital in] [ital situ]. Recent work on the structure of Au single crystal electrodes has shown the need to merge appropriate electrochemical cell designs to work on standard four-circle diffractometers. In this report, a new electrochemical cell is described for use in [ital in] [ital situ] structure determination. The cell provides excellent electrochemical control of the electrode surface, as determined by the cyclic voltammagram, in conjunction with the x-ray studies.
  • We presented a focal construct geometry (FCG) method for high intensity energy dispersive X-ray diffraction by utilizing a home-made ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL). The ESBC was employed to focus the X-rays from a conventional laboratory source into a small focal spot and to produce an annular X-ray beam in the far-field. Additionally, diffracted polychromatic X-rays were confocally collected by the PPXRL attached to a stationary energy-resolved detector. Our FCG method based on ESBC and PPXRL had achieved relatively high intensity diffraction peaks and effectively narrowed the diffraction peak width which was helpful inmore » improving the potential d-spacing resolution for material phase analysis.« less
  • The underpotential deposition of Pb was studied on Cu(111) single crystal surfaces prepared both by a novel electropolishing procedure and by sputtering/annealing in ultrahigh vacuum. Identical results were found with both methods. Pb atoms are deposited underpotentially on Cu(111) into a compact nonrotated hexagonal overlayer. The measured Pb coverage at saturation is 53% with respect to the Cu(111) substrate and is identical to the packing density of the (111) plane of bulk Pb. The presence of Cl in the supporting electrolyte has a strong effect on the potential region where deposition/stripping occurs and on the reversibility of the reaction. 43more » refs., 8 figs., 1 tab.« less
  • The electrochemical oxidation of propylene carbonate containing 1.0 mol/dm{sup 3} LiClO{sub 4} was investigated with the aid of in situ Fourier transform infrared spectroscopy. The subtractively normalized interfacial Fourier transform infrared spectra were obtained for potentials ranging from 4.0 V vs. Li/Li{sup +} to 5.0 V vs. Li/Li{sup +}. From these spectra it is concluded that propylene carbonate decomposes at more positive potentials than does 4.2 V vs. Li/Li{sup +} on an Ni electrode. The decomposition products adsorbed on the electrode surface and then gradually dissolved in the electrolyte. From the spectral change for carbonyl groups, it can be seenmore » that the ring opening reaction of propylene carbonate is included in the decomposition process of propylene carbonate electrolytes. On the other hand, the oxidation of propylene carbonate on Al, Pt, and Au electrodes was not observed in the range of potentials investigated. Thus, the oxidation of propylene carbonate containing 1.0 mol/dm{sup 3} LiClO{sub 4} must depend on the electrode material. When the electrode surfaces were analyzed by X-ray photoelectron spectroscopy, those of the Ni and Al electrodes were found to be covered with their oxides, but oxides were not observed on the Pt or Au electrodes. It is therefore concluded that Ni oxide probably contributes to the decomposition of propylene carbonate.« less
  • Strontium substituted lanthanum manganates(III)(IV), La{sub 1{minus}x}Sr{sub x}MnO{sub 3+{delta}} (LSM) are cathode materials for high temperature solid oxide fuel cells/SOFC. Time resolved synchrotron X-ray powder diffraction methods have been used to study the kinetics of oxidation of lanthanum strontium manganates(III, IV) in a flow of oxygen. The process studied is La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00} + {delta}/2O{sub 2}{leftrightarrow}La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00+{delta}} (for x = 0.00, 0.10, 0.15). A contraction of the unit cell is observed on oxidation of the materials. The unit cell volume changes linearly with the mean oxidation state of the manganese. Rate constants for the process can consequently bemore » determined from time resolved X-ray diffractograms. The reactions follow first-order kinetics. Arrhenius plots based on rate constants determined at 4 temperatures in the range 700--900 C are linear as an indication that only one rate determining step is involved. The activation energy for oxidation is 136 kJmol{sup {minus}1} for LaMnO{sub 3.00}, 179 kJmol{sup {minus}1} for La{sub 0.90}Sr{sub 0.10}Mn{sub 1.01}O{sub 3.01}, and 160 kJmol{sup {minus}1} for La{sub 0.84}Sr{sub 0.15}Mn{sub 1.01}O{sub 3.00}.« less