skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach

Abstract

The in situ molecular characterization of reaction intermediates and products at electrode-electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode-electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability we report the first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode-electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode-electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode-electrolyte interface.

Authors:
; ; ; ; ; ORCiD logo; ORCiD logo; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1339805
Report Number(s):
PNNL-SA-122793
Journal ID: ISSN 0003-2700; 48143; 47299; 49188; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Analytical Chemistry; Journal Volume: 89; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Wang, Zhaoying, Zhang, Yanyan, Liu, Bingwen, Wu, Kui, Thevuthasan, Suntharampillai, Baer, Donald R., Zhu, Zihua, Yu, Xiao-Ying, and Wang, Fuyi. In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach. United States: N. p., 2017. Web. doi:10.1021/acs.analchem.6b04189.
Wang, Zhaoying, Zhang, Yanyan, Liu, Bingwen, Wu, Kui, Thevuthasan, Suntharampillai, Baer, Donald R., Zhu, Zihua, Yu, Xiao-Ying, & Wang, Fuyi. In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach. United States. doi:10.1021/acs.analchem.6b04189.
Wang, Zhaoying, Zhang, Yanyan, Liu, Bingwen, Wu, Kui, Thevuthasan, Suntharampillai, Baer, Donald R., Zhu, Zihua, Yu, Xiao-Ying, and Wang, Fuyi. Tue . "In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach". United States. doi:10.1021/acs.analchem.6b04189.
@article{osti_1339805,
title = {In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach},
author = {Wang, Zhaoying and Zhang, Yanyan and Liu, Bingwen and Wu, Kui and Thevuthasan, Suntharampillai and Baer, Donald R. and Zhu, Zihua and Yu, Xiao-Ying and Wang, Fuyi},
abstractNote = {The in situ molecular characterization of reaction intermediates and products at electrode-electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode-electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability we report the first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode-electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode-electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode-electrolyte interface.},
doi = {10.1021/acs.analchem.6b04189},
journal = {Analytical Chemistry},
number = 1,
volume = 89,
place = {United States},
year = {Tue Jan 03 00:00:00 EST 2017},
month = {Tue Jan 03 00:00:00 EST 2017}
}
  • A portable vacuum interface allowing direct probing of the electrode-electrolyte interface was developed. A classical electrochemical system consisting of gold working electrode, platinum counter electrode, platinum reference electrode, and potassium iodide electrolyte was used to demonstrate real-time observation of the gold iodide adlayer on the electrode and chemical species as a result of redox reactions using cyclic voltammetry (CV) and the time-of-flight secondary ion mass spectrometry (ToF-SIMS, a vacuum-based surface analytical technique) simultaneously. This microfluidic electrochemical probe provides a new way to investigate the surface region with adsorbed molecules and region of diffused layer with chemical speciation in liquids inmore » situ by surface sensitive techniques.« less
  • The electrochemical interface between the solid electrode and liquid electrolyte has long been studied because of its importance in electrical energy storage, material synthesis, catalysis, and energy conversions.1 However, such interfaces are complex and extremely difficult to observe directly and are poorly under-stood due to lack of true in situ tools.2 Although electrochemical techniques have been widely used to investigate such interfaces, they are based on macroscopic models or current changes that could not provide direct ionic and molecular information of the interfacial structure. Many in situ and ex situ spectroscopy and microscopy techniques have been used to study themore » solid–liquid (s–l) interface.3,4 In situ TEM in sealed liquid cells has notably become a popular choice to provide structural information of s–l at the atomic level.5,6 However, real-time spatial mapping of the ionic and molecular intermediate species at the dynamic inter-face still remains a key challenge.« less
  • The rate processes of electrochemical reactions were clarified in a CH{sub 4}-H{sub 2}O system at the interface of a porous Pt electrode/Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} electrolyte. Direct-current polarization measurements and ac impedance spectroscopy were made with gas analysis before and after the reaction at 1,073 K. The authors proposed an analytical method to determine the rates of electrochemical reactions taking place in parallel. When the ratio p(H{sub 2}O)/p(CH{sub 4}) of the inlet gas was close to zero, the observed relationship between the polarization current and electrode potential was interpreted by the electrochemical oxidation processes of H{sub 2}, CO, C,more » and CH{sub 4} in parallel using the proposed method. For example, the ratio of the oxidation rates for C/CO/CH{sub 4}/H{sub 2} is 1/1.3 x 10/1.9 x 10{sup 2}/2.8 x 10{sup 3} at E = {minus}600 mV vs. air. The result was obtained under very low CH{sub 4} concentration. The estimated oxidation rates of H{sub 2} and CO as functions of the electrode potential were described by the model proposed by Mizusaki et al. for the reaction of H{sub 2}-H{sub 2}O and CO-CO{sub 2}.« less
  • A nanometer thick passivation layer will spontaneously form on Li-metal in battery applications due to electrolyte reduction reactions. This passivation layer in rechargeable batteries must have “selective” transport properties: blocking electrons from attacking the electrolytes, while allowing Li + ion to pass through so the electrochemical reactions can continue. The classical description of the electrochemical reaction, Li + + e → Li 0, occurring at the Li-metal|electrolyte interface is now complicated by the passivation layer and will reply on the coupling of electronic and ionic degrees of freedom in the layer. We consider the passivation layer, called “solid electrolyte interphasemore » (SEI)”, as “the most important but the least understood in rechargeable Li-ion batteries,” partly due to the lack of understanding of its structure–property relationship. In predictive modeling, starting from the ab initio level, we find that it is an important tool to understand the nanoscale processes and materials properties governing the interfacial charge transfer reaction at the Li-metal|SEI|electrolyte interface. Here, we demonstrate pristine Li-metal surfaces indeed dissolve in organic carbonate electrolytes without the SEI layer. Based on joint modeling and experimental results, we point out that the well-known two-layer structure of SEI also exhibits two different Li + ion transport mechanisms. The SEI has a porous (organic) outer layer permeable to both Li + and anions (dissolved in electrolyte), and a dense (inorganic) inner layer facilitate only Li + transport. This two-layer/two-mechanism diffusion model suggests only the dense inorganic layer is effective at protecting Li-metal in electrolytes. This model suggests a strategy to deconvolute the structure–property relationships of the SEI by analyzing an idealized SEI composed of major components, such as Li 2CO 3, LiF, Li 2O, and their mixtures. After sorting out the Li+ ion diffusion carriers and their diffusion pathways, we design methods to accelerate the Li + ion conductivity by doping and by using heterogonous structure designs. We will predict the electron tunneling barriers and connect them with measurable first cycle irreversible capacity loss. We note that the SEI not only affects Li + and e transport, but it can also impose a potential drop near the Li-metal|SEI interface. Our challenge is to fully describe the electrochemical reactions at the Li -metal|SEI|electrolyte interface. This will be the subject of ongoing efforts.« less
  • The electrochemical behavior and electrocatalytic properties of the complex of Cu/sup 2 +/ with poly(4-vinylpyridine) were studied at a pyrolytic graphite electrode. It was shown that not all copper ions of the polymer films are in an electrochemically active state when the process is conducted under nonequilibrium conditions. The counterion type has an important effect of the electrochemical behavior of the polymer film electrode. The complex displays electrocatalytic activity in molecular-oxygen electroreduction in neutral buffer solutions; the activity depends on the degree of saturation of the polymer film with copper ions.