除了声之外:四面体作为初始离子导体
Shriparna Mukherjee1, David J Voneshen2,3, Andrew Duff4
1Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6DX, UK.
Advanced materials (Deerfield Beach, Fla.)
|August 15, 2023
概括
研究人员在四面体中发现了初始的离子导电,使得超低的导热率能够在没有在类似液体的热电材料中看到的降解的情况下实现.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 热化学 热化学 热化学
背景情况:
- 超低导热率对于热电能收获,热屏障涂层和光电子技术至关重要.
- 高移动的离子会破坏声子的传播,降低热导率,但会导致液态热电材料的材料降解.
- 降解通过离子迁移和阴极金属沉积发生,限制了实际应用.
研究的目的:
- 确定一种实现超低导热的新机制.
- 为了克服与类似液体的热电材料相关的降解问题.
- 探索移动离子在已建立的热电材料,如四面体的行为.
主要方法:
- 中子光谱学被用来研究离子动力学.
- 用分子动力学 (MD) 模拟来建模离子行为.
- 分析的重点是铜离子在四面体晶体结构中的移动性.
主要成果:
- 刚开始的离子导电被确定为超低导热性的机制.
- 四面体中的铜离子虽然在200K以上是可移动的,但仍然被限制在晶体内.
- 这种限制可以防止在类似液体的材料中出现的有害离子迁移和降解.
结论:
- 刚开始的离子导电提供了一条途径,在没有材料降解的情况下达到超低的导热率.
- 四面体石是表现出这种有益行为的材料的例子.
- 未来用于热电应用的材料设计应考虑具有初始离子导电的系统.
相关概念视频
Ionic Crystal Structures
14.4K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
14.4K
Ionic Bonding and Electron Transfer
41.7K
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
41.7K
Metallic Solids
18.5K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
18.5K
Electrolyte and Nonelectrolyte Solutions
63.3K
Substances that undergo either a physical or a chemical change in solution to yield ions that can conduct electricity are called electrolytes. If a substance yields ions in solution, that is, if the compound undergoes 100% dissociation, then the substance is a strong electrolyte. Complete dissociation is indicated by a single forward arrow. For example, water-soluble ionic compounds like sodium chloride dissociate into sodium cations and chloride anions in aqueous solution.
63.3K
Bonding in Metals
47.5K
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
47.5K
Ionic Bonds
118.6K
Overview
When atoms gain or lose electrons to achieve a more stable electron configuration they form ions. Ionic bonds are electrostatic attractions between ions with opposite charges. Ionic compounds are rigid and brittle when solid and may dissociate into their constituent ions in water. Covalent compounds, by contrast, remain intact unless a chemical reaction breaks them.
Opposing Charges Hold Ions Together in Ionic Compounds
Ionic bonds are reversible electrostatic interactions between ions...
When atoms gain or lose electrons to achieve a more stable electron configuration they form ions. Ionic bonds are electrostatic attractions between ions with opposite charges. Ionic compounds are rigid and brittle when solid and may dissociate into their constituent ions in water. Covalent compounds, by contrast, remain intact unless a chemical reaction breaks them.
Opposing Charges Hold Ions Together in Ionic Compounds
Ionic bonds are reversible electrostatic interactions between ions...
118.6K


