在结构上,NaTFSI和NaFSI基于盐的盐水电解质是相似的还是不同的?
Navneet Singh1, Hemant K Kashyap1
1Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
The journal of physical chemistry. B
|July 24, 2024
概括
盐水电解质 (WiSE) 提供安全性和稳定性. 分子动力学模拟显示了NaTFSI和NaFSI电解质之间的明显结构差异,NaFSI在高度下显示了离子协调和水中破坏的增加.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 计算化学的计算化学
背景情况:
- 盐水电解质 (WiSEs) 是先进的电解质系统,以其增强的电化学稳定性和固有的不易燃性而闻名.
- 了解WiSE中的离子溶剂相互作用和结构组织对于优化其在电化学设备中的性能至关重要.
研究的目的:
- 为了研究基于二三甲硫胺 (NaTFSI) 和二硫胺 (NaFSI) 的水性电解质在广泛的度范围内的结构组织.
- 通过分子动力学模拟,阐明NaTFSI和NaFSIWiSEs中离子协调和水分子行为的差异.
主要方法:
- 用全原子分子动力学 (MD) 模拟来建模NaTFSI和NaFSI水性电解质,从稀释到高度缩的方案.
- 进行了对离子周围水分子,离子-离子协调和水-水结合网络的分析.
- 模拟的X射线散射模式被生成以确定结构秩序.
主要成果:
- 在NaTFSI电解质中,Na+离子是稳定水的,TFSI离子与水的相互作用比与Na+或其他TFSI离子的相互作用更大.
- 在NaFSI电解质中,随着度的增加,Na+水分减少,导致Na+-FSI相互作用的增强和高度水结构的破坏.
- 这两种电解质都表现出中等范围的排序 (富含离子和富含水/Na+的区域),以模拟的X射线散射中的低q峰值表示,随着盐度的增加,其特征长度尺度下降.
结论:
- 在NaTFSI和NaFSIWiSEs之间,结构组织和离子溶解行为显著不同,特别是在高盐度下.
- 在高度下,NaFSI电解质显示向阴离子主导网络的过渡,比NaTFSI更严重地破坏了水结构.
- 在两种系统中观察到的中等范围的排序表明,缩的电解质中存在一个一般的结构图案,受盐度的影响.
相关概念视频
Ionic Strength: Overview
1.4K
The ionic strength of a solution is a quantitative way of expressing the total electrolyte concentration of a solution. This concept was first introduced in 1921 by two American physical chemists, Gilbert N. Lewis and Merle Randall, while describing the activity coefficient of strong electrolytes. During the calculation of ionic strength (I or μ), all the cations and anions are considered. However, the concentration (c) of an ion with a greater charge number (z) has a greater contribution...
1.4K
Ionic Strength: Effects on Chemical Equilibria
1.4K
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary...
In this solution, the primary...
1.4K
Ions as Acids and Bases
23.7K
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
23.7K
Solubility of Ionic Compounds
62.9K
Solubility is the measure of the maximum amount of solute that can be dissolved in a given quantity of solvent at a given temperature and pressure. Solubility is usually measured in molarity (M) or moles per liter (mol/L). A compound is termed soluble if it dissolves in water.
62.9K
Solvents
64.5K
A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a solvent and a solute combine, they form a solution - a homogenous mixture of both the solvent and the solute. Water is a universal biological solvent. Its polar structure allows it to dissolve many other polar compounds. The ability of water to dissolve is governed by a balance between water molecules binding to each other and binding to the solute.
A...
A...
64.5K
Precipitation Reactions
50.5K
In a precipitation reaction, aqueous solutions of soluble salts react to give an insoluble ionic compound – the precipitate. The reaction occurs when oppositely charged ions in solution overcome their attraction for water and bind to each other, forming a precipitate that separates out from the solution. Since such reactions involve the exchange of ions between ionic compounds in aqueous solution, they are also referred to as double displacement, double replacement, exchange reactions, or...
50.5K


