Simultaneous Thermal Analysis-mass Spectrometry Research Articles

Thermal Stability and the Effect of Water on Hydrogen Fluoride Generation in Lithium-Ion Battery Electrolytes Containing LiPF6

Lithium-ion batteries (LIBs) have been used as electrochemical energy storage devices in various fields, ranging from mobile phones to electric vehicles. LIBs are composed of a positive electrode, a negative electrode, an electrolyte, and a binder. Among them, electrolytes consist of organic solvents and lithium ion conducting salts. The electrolytes used in LIBs are mostly linear and cyclic alkyl carbonates. These electrolytes are usually based on their combinations to allow the use of Li as the anodic active component, resulting in the high power and energy density of batteries. However, these organic electrolytes have high volatility and flammability that pose a serious safety issue when exposed to extreme conditions such as elevated temperatures. At that time, these electrolytes can react with active electrode materials and release a considerable amount of heat and gas. In this study, a simultaneous thermal analysis-mass spectrometry analysis was performed on six different organic solvents to examine the effect of water on hydrogen fluoride (HF) generation temperature in the electrolyte of a LIB. The electrolytes used in the experiment were anhydrous diethyl carbonate, 1,2-dimethoxyethane, ethylene carbonate, 1,3-dioxolane, tetrahydrofurfuryl alcohol, and 2-methyl-tetrahydrofuran, each containing LiPF6. The HF formation temperature was observed and compared with that when water entered the electrolyte exposed to high-temperature conditions such as fire.

Study of the Adsorption Activity of Skeletal Nickel with Respect to Reactive Hydrogen by Simultaneous Thermal Analysis Mass Spectrometry

A method for the determination of the total amounts and physical parameters of adsorbed individual hydrogen species on the surface and in the bulk of metal catalysts of liquid-phase hydrogenation reactions by simultaneous thermal analysis mass spectrometry was proposed. The adsorptions of reactive hydrogen on a skeletal nickel catalyst in an aqueous medium were estimated. The concentrations of metal-hydrogen complexes with different binding energies on the surface of the catalyst in the liquid phase were determined by a direct experimental method.

Application of simultaneous thermal analysis mass spectrometry and stable carbon isotope analysis in a carbon sequestration study

The simultaneous analysis of evolved gases and the determination of stable isotope composition (delta13C) as part of a thermal analysis experiment have been used to (a) distinguish bulk chemical hosts for carbon (C) and nitrogen (N) within a soil and (b) track labelled C within a soil sequestration experiment. C3 and C4 dung was applied to a pasture soil, and soil samples taken for analysis. The results of thermogravimetry-differential scanning calorimetry-quadrupole mass spectrometry-isotope ratio mass spectrometry (TG-DSC-QMS-IRMS) show that the proportion of more refractory C (lignin-like) is greater for the dungs than for the soil organic matter (SOM), and that this increases with time within the soil. Analysis of evolved gases shows that nitrogen is associated with the decomposition of more refractory C, and is not so strongly associated with the labile C component. IRMS analysis distinguished C3 and C4 dung, and allowed the amount of C from these sources to be estimated for the soil samples. Most dung C enters the refractory SOM fraction. This paper demonstrates the potential of TG-DSC-QMS-IRMS in the investigation of SOM.

Thermal properties of starch succinates

Starch succinates are starch derivatives used as binders and thickening agents in foods, tablet disintegrants in pharmaceuticals, surface sizing agents and coating binders in paper. A series of starch esters with different degrees of substitution (DS = 0.008–0.639) prepared by reactive extrusion were studied. Potato, wheat and corn starch were investigated. Thermooxidative behaviour of starch succinates was studied by simultaneous thermal analysis–mass spectrometry (STA–MS) method. The thermal stability of starch esters depends on the degree of substitution (DS). With an increase in DS, thermal stability increases. The major differential thermogravimetric (DTG) peaks are observed below 300 °C. The most abundant ions found are H 2O + and CO 2 +.

State Analysis of Carbonaceous Components in Coal Fly Ash by Simultaneous Thermal Analysis-Mass Spectrometry

The state of carbonaceous components in coal fly ash fractionated by particle size and density was investigated by means of simultaneous thermal analysis-mass spectrometry in an inert atmosphere (He) and a quasi air atmosphere (O2/He=20/80 vol%). The carbonaceous components were characterized by their thermal degradation behavior and evolved gas species observed in each condition. Their components were proved to exist in three different states: the fractions with larger particle size (>20 μm) and medium density (2.0 – 2.4 g/cm3) mostly consist of elemental carbon, the smaller particle size fractions (<5 μm) organic and elemental carbon, and the higher density fractions (2.8 – 3.2 g/cm3) carbonate. In addition to the carbonaceous components, the existence of sulfate and hydroxide was suggested.

The ammonium ion and the ammine ligand as internal reducing agents for platinum-group-metal complexes: A comment

Simultaneous thermal analysis-mass spectrometry and time resolved X-ray powder diffraction of the thermal behaviour of such platinum-group-metal complexes as (NH 4[PtCl 6], [Pd(NH 3) 2Cl 2] or (NH 4)3[RhCl 6](H 2O), and preparative procedures, clearly reveal that the initial step to produce finely divided metal powder must be the internal redox reaction between the N 3− of the ammonium ion/ammine ligand and the noble-metal ion (M n+; n = 2, 3, 4). It is certainly not the decomposition to binary components followed by their decomposition to the elements or reaction to oxides as has been reported quite recently.

Simultaneous thermal analysis-mass spectrometry on lubricant systems and additives

In order to determine characteristic thermal analysis data of lubricant systems and additives, simultaneous thermal analysis-mass spectrometry was applied in air and argon atmospheres. In addition, investigations by means of differential scanning calorimetry and thermogravimetry were carried out in air and nitrogen flows. The thermobalance was coupled with a sampling device for the collection of the released volatiles and further gas Chromatographic analysis.

Thermal analysis-mass spectrometry and thermogravimetric adsorption on fire retardants

Simultaneous thermal analysis mass spectrometry and an off-line combustion technique were applied to different fire retardants. The samples were commercial products (phosphorus ester compounds containing chlorine substituents). A thermogravimetric adsorption device was developed to adsorb the degradation products of the samples depending on the temperature. Identification of the adsorbed compounds was carried out using gas chromatography- mass spectrometry.

Simultaneous thermal analysis-mass spectrometric investigations of volatiles released from coal samples

This paper deals with the application of simultaneous thermal analysis-mass spectrometry in coal analysis, especially regarding the identification of volatiles released during a temperature controlled program. The analyses have been carried out in dynamic air, in an argon or nitrogen atmosphere and in high vacuum showing the different combustion characteristics by a subtraction method. The evolution profiles of typical structural elements of coal like homologous series of benzene, toluene and xylene isomers, polynuclear aromatic hydro-carbons sulfur dioxide and nitrogen dioxide have been recorded applying different kinds of acquisition modes (analog or computer aided).