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5. Methyl p-toluenesulfonate as A Highly Effective Film-Forming Additive to Improve the Performance of A High-Voltage LiMn2O4 Cathode.

Author

Hamidi, Susan, Javanbakht, Mehran, and Mousazadeh, Mohammad Hassan

Subjects
IONIZATION energy, DENSITY functional theory, ELECTROCHEMICAL analysis, IMPEDANCE spectroscopy, HIGH voltages
Abstract

The current study explores the film forming ability of a new additive Methyl p-toluene sulfonate (MPTS) on the LiMn2O4 (LMO) electrode and its effect on the electrochemical characteristics of lithium-ion battery. Based on the density functional theory analysis of the ionization energy (AIE) of MPTS and carbonate solvents, it was found that MPTS possesses the lowest AIE at 693.2 kJ/mol, suggesting a higher susceptibility to oxidation compared to the electrolyte solvents. Electrochemical and physicochemical analyses including linear sweep voltammetry, electrochemical impedance spectroscopy, field-emission scanning microscopy, indicated that the electrolyte with MPTS is prone to create a protective film with low impedance on the cathode electrode, which enhances the stability of the electrolyte and electrode upon battery cycling. The LMO/Li half-cell with 1.5% MPTS exhibits outstanding cyclic performance, retaining 90.53% of its capacity after 100 cycles, in comparison to 81.84% for the pristine electrolyte at high voltage. This improvement is because of the creation of a protective sulfur-containing layer on the cathode surface, which effectively prevents electrolyte degradation, reduces interfacial impedance, and enhances overall battery performance. [ABSTRACT FROM AUTHOR]

Published
2024
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10. A renewable bio-based epoxy resin with improved mechanical performance that can compete with DGEBA

Author

Nikafshar, Saeid, Zabihi, Omid, Hamidi, Susan, Moradi, Yousef, Barzegar, Saeed, Ahmadi, Mojtaba, Naebe, Minoo, Nikafshar, Saeid, Zabihi, Omid, Hamidi, Susan, Moradi, Yousef, Barzegar, Saeed, Ahmadi, Mojtaba, and Naebe, Minoo

Abstract

The aim of this study is to find a suitable substitution for diglycidyl ether bisphenol A (DGEBA) to avoid the devastating side effects of bisphenol A. Vanillin, an aromatic compound, was used as a renewable material to synthesize a bio-based epoxy resin. The structure of the vanillin-based epoxy resin was confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The major drawback of bio-based epoxy resins is their poor mechanical properties preventing them from competing with petroleum based epoxy resins such as DGEBA. Herein, a prepared calcium nitrate solution as an inorganic accelerator was used to accelerate the curing reaction of bio-based epoxy resin which reduced curing times as well as improving significantly the mechanical properties e.g., tensile strength, pull-off strength, and Izod impact strength. Differential scanning calorimetry (DSC) analysis was used to investigate the curing process and thermal properties of the vanillin-based epoxy resin with and without inorganic accelerators and also DGEBA without accelerators. The results showed that in the presence of 2 wt% inorganic accelerator, the initial onset curing temperature of vanillin-based epoxy resin was reduced from 60.1 °C to 8.5 °C, while the initial onset curing temperature of DGEBA was 55.8 °C. In addition, tensile strength and Izod impact strength of the vanillin-based epoxy system in the presence of inorganic accelerators increased in comparison to the DGEBA system. Moreover, in order to study the effect of inorganic accelerators on the toughness of the synthesized vanillin-based epoxy resin, fracture surfaces from Izod impact strength tests were observed using scanning electron microscopy (SEM) which confirmed improving mechanical properties.

Published
2017

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