Secondary ion mass spectrometry (SIMS) and its application to chemical weathering

Abstract

Secondary ion mass spectrometry (SIMS) is the mass spectrometry of atomic species which are emitted when a solid surface is bombarded by an energetic primary ion beam. By continually bombarding the surface of the sample with the ion beam, the atoms making up the material being studied are sputtered away. The secondary ions emitted from the surface are continually analyzed and their intensities recorded over time. The secondary ion intensities are proportional to the concentration of elements in the sample, thereby producing a semiquantitative concentration depth profile. The depth profile provides an illustration of the chemical composition of a sample as a function of depth through the surface. The SIMS technique has been applied to a wide variety of surface analytical problems and can easily be used to analyze reacted glass and mineral surfaces which have been exposed to weathering solutions. Traditional experimental studies of chemical weathering were based primarily on the analyses of aqueous solutions generated during leaching experiments. Such studies have provided valuable information concerning rates and stoichiometry of mineral dissolution reactions but have led to some confusion and much speculation regarding the mechanisms of surface processes. SIMS analyses of the surfaces of dissolving glasses and plagioclase feldspars have recently been used to help resolve a number of unanswered questions. For example, SIMS analyses of dissolving feldspars have shown how the chemical composition of reacted surfaces and depth of attack vary, depending on the composition of the mineral, the pH of the leaching solution, and the presence of dissolved salts and complex‐forming organic ligands.

Physical Properties of Interfacial Layers Developed on Weathered Silicates: A Case Study Based on Labradorite Feldspar

“…The first hypothesis (referred to as the "leached layer" hypothesis) has represented the prevailing paradigm for decades 27,28 . It is consistent with ion and photon probe results suggesting that the elemental profiles of reactive species and reaction products are anticorrelated within the ASSL [29][30][31][32][33][34][35][36][37][38] . The alternative "dissolution-reprecipitation" hypothesis 39 is supported by transmission 4 electron microscopy observations that indicate an absence of compositional gradients within the ASSL 13 and atom-probe tomography measurements of altered glass samples that reveal an atomically sharp inner interface {Gin, 2017; Hellmann, 2015}, which has led to the suggestion that the compositional gradients observed in the ion and photon probe results may be artifacts associated with low lateral resolution 20 .…”

“…The first of these concerns whether ASSLs form by leaching of soluble elements (e.g., Ca, K, Mg, Na) from the primary mineral or, alternatively, by dissolution of the primary mineral followed by precipitation of an amorphous Si-rich phase. The former hypothesis (referred to as the “leached layer” hypothesis) has represented the prevailing paradigm for decades. , It is consistent with ion and photon probe results suggesting that the elemental profiles of reactive species and reaction products are anticorrelated within the ASSL. − The alternative “dissolution–reprecipitation” hypothesis is supported by transmission electron microscopy observations that indicate an absence of compositional gradients within the ASSL and by atom-probe tomography measurements of altered glass samples that reveal an atomically sharp inner interface, , which has led to the suggestion that the compositional gradients observed in the ion and photon probe results may be artifacts associated with low lateral resolution . It is also supported by indirect evidence, in some cases, of fluid–mineral interactions occurring through the layer and of mineral dissolution at the interface between the ASSL and the pristine mineral surface due to the presence of a thin fluid film at the inner interface …”

Fluorine Chemistry in Rechargeable Batteries: Challenges, Progress, and Perspectives

“…These secondary ions pass through a flight tube, and then they are continuously analyzed, with the corresponding intensities being recorded over time. The ion intensities are proportional to element contents, thus forming a semiquantitative concentration-depth image for probing the chemical composition of the SEI layers. ,− Peled et al were pioneers in applying SIMS for investigating the mechanism of SEI formation on the basal plane and cross-sectional edge of graphite. Since then, depth profiling by SIMS has been utilized widely to probe the SEIs generated on Cu, , graphite, ,,,,− Si, ,,− Li metal, ,,,− etc., demonstrating its ability to analyze the dynamic properties of SEI layers with high sensitivity.…”

A Brief Review on Solid Electrolyte Interphase Composition Characterization Technology for Lithium Metal Batteries: Challenges and Perspectives

“…By continually bombarding the surface of the sample with the ion beam, the atoms called secondary ions are sputtered away, carrying the information on the material, and then they are continually analyzed with their intensities being recorded over time. 131 The ion intensities are proportional to the concentration of elements in the sample, Xu and co-workers 67 monitored the real-time formation of SEI by the newly developed in situ liquid-SIMS (Figure 13). First, a thin Si 3 N 4 membrane is used to separate the liquid from a high vacuum.…”

“…Secondary ion mass spectrometry is the mass spectrometry of atomic species which are emitted when a solid surface is bombarded by an energetic primary ion beam. By continually bombarding the surface of the sample with the ion beam, the atoms called secondary ions are sputtered away, carrying the information on the material, and then they are continually analyzed with their intensities being recorded over time . The ion intensities are proportional to the concentration of elements in the sample, thereby profiling a semiquantitative concentration depth image, providing an illustration of the chemical composition of SEI.…”