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Revisiting the structure, interaction, and dynamical property of ionic liquid from the deep learning force field
No full textRational understanding of interaction and structure of ionic liquids (ILs) is vital for their application in super -capacitors. The force field trained by machine learning has aroused considerable interest in the molecular design of ILs, which can effectively balance the competition between computational accuracy and efficiency. In this work, a new deep learning force field (DPFF) for 10 different ILs was obtained, where the dataset for atomic energy and force was prepared via the ab initio molecular dynamics (MD) simulation. Using the trained DPFF, the ns-long MD simulations for various ILs were performed successfully. Combining the error analysis on atomic energy, distribution of bonds and angles, and potential energy, one can prove that the MD simulation with DPFF can describe the force and energy of ILs with ab initio precision. Meanwhile, the analysis of the vibrational spectrum and hydrogen bond suggests that the DPFF can also predict the coupling nature between coulombic and hydrogen bonding interactions within ILs reasonably. Furthermore, the DPFF for ILs is trained to extend to the bulk system. Hence, DPFF, possessing high accuracy and low computational cost, can serve as an effective tool for the molecular design of new ILs-based electrolytes for high-performance energy storage devices
Impacts of Ce dopants on the hydrogen storage performance of Ti-Cr-V alloys
No full textVanadium-based alloys are considered to be one of the most promising hydrogen storage materials due to their high hydrogen storage capacity under ambient conditions. However, their complex activation at high temperature and poor stability pose serious challenges for large-scale applications. In this work, a series of TiCr3V16Cex (x = 0, 0.1, 0.2, 0.4, 1) hydrogen storage alloys were developed with different Ce contents using arc melting. The hydrogen storage and desorption performance, activation mechanism, and hydrogen ab-sorption mechanism of the prepared alloys were investigated. Physical characterization confirms that the alloy is body-centered cubic (BCC) with Ce dopants, which exist in the form of oxides. The pressure-composition-temperature (PCT) test showed that the hydrogen storage plateau pressure of the Ce-doped alloy is increased compared to the Ce-free counterparts, while the hydrogen storage capacity decreased slightly with increasing Ce content. In addition, the influence of Ce doping on the alloy kinetics and ther-modynamics is also discussed. The results showed that the TiCr3V16Cex (x = 0.2, 0.4, 1) alloys could absorb and release hydrogen at room temperature without activation. As an optimum, the TiCr3V16Ce0.2 alloy shows a hydrogen absorption rate of up to 3.69 wt%, and an effective hydrogen desorption capacity of 2.29 wt% at 25 degrees C. After hydrogen absorption and desorption cycles, the alloy almost maintains its original capacity. The Ce-doped BCC alloy developed in this work provides a new route to achieve high hydrogen storage performance under mild conditions.(c) 2022 Elsevier B.V. All rights reserved
Impacts of Ce dopants on the hydrogen storage performance of Ti-Cr-V alloys
No full textVanadium-based alloys are considered to be one of the most promising hydrogen storage materials due to their high hydrogen storage capacity under ambient conditions. However, their complex activation at high temperature and poor stability pose serious challenges for large-scale applications. In this work, a series of TiCr3V16Cex (x = 0, 0.1, 0.2, 0.4, 1) hydrogen storage alloys were developed with different Ce contents using arc melting. The hydrogen storage and desorption performance, activation mechanism, and hydrogen ab-sorption mechanism of the prepared alloys were investigated. Physical characterization confirms that the alloy is body-centered cubic (BCC) with Ce dopants, which exist in the form of oxides. The pressure-composition-temperature (PCT) test showed that the hydrogen storage plateau pressure of the Ce-doped alloy is increased compared to the Ce-free counterparts, while the hydrogen storage capacity decreased slightly with increasing Ce content. In addition, the influence of Ce doping on the alloy kinetics and ther-modynamics is also discussed. The results showed that the TiCr3V16Cex (x = 0.2, 0.4, 1) alloys could absorb and release hydrogen at room temperature without activation. As an optimum, the TiCr3V16Ce0.2 alloy shows a hydrogen absorption rate of up to 3.69 wt%, and an effective hydrogen desorption capacity of 2.29 wt% at 25 degrees C. After hydrogen absorption and desorption cycles, the alloy almost maintains its original capacity. The Ce-doped BCC alloy developed in this work provides a new route to achieve high hydrogen storage performance under mild conditions.(c) 2022 Elsevier B.V. All rights reserved
Role of Na2O and TiO2 on viscosity and structure of Sodium-Titanium-bearing slag
No full textThe viscosities of Na2O-TiO2-SiO2-CaO-MgO-Al2O3 slags were measured to enhance understanding of the effect of Na2O and TiO2 on the viscous behavior. An increase in the Na2O content lowered the viscosity but adding TiO2 increased the viscosity. The transformation of the structural units was investigated using in-situ temperature -dependent Raman spectra. TiO2 primarily existed in the slag system in the form of [TiO4]4-monomer, which acted as a network former. As Na2O increased, the chain structure (Q2, [Ti2O6]4-or [SiTiO6]4-) was broken by O2-ions to form tetrahedral monomer (Q0, [TiO4]4-or [SiO4]4-), which lowered the degree of polymerization. Adding TiO2, Q2 chain was formed by TiO2 and Q0 monomer to enhance the polymerization degree of the slag, resulting in the increase of the viscosity. Based on the Raman spectra and the hole theory, a quantitative rela-tionship, ln eta=3.7+0.88ln((Q2)/(Q0)2), between the structural units and viscosity of sodium-titanium-bearing slag was established
