较小的硫分子承诺更好的硫电池
Sen Xin1, Lin Gu, Na-Hong Zhao
1Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, PR China.
Journal of the American Chemical Society
|October 30, 2012
概括
研究人员使用小硫分子开发了一种新的硫电池. 这种方法通过防止容量衰减,显著提高了电池性能和寿命,为高能储能解决方案铺平了道路.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 储能 储能 储能 储能 储能 储能
背景情况:
- 硫 (Li-S) 电池具有较高的理论能量密度,超过目前的离子技术.
- 阻碍Li-S电池应用的关键挑战包括硫阴极导电性差以及由可溶性多硫化物中间体引起的容量色.
- 由于聚硫化物形成而导致的硫损失仍然是实用的Li-S电池的关键障碍.
研究的目的:
- 为了解决硫电池的容量衰减问题.
- 开发一种新的阴极材料,减轻硫损失.
- 为了提高Li-S电池的电化学性能和稳定性.
主要方法:
- 在导电微孔碳基质中合成转移稳定的小硫分子 (S(2-4) .
- 使用封闭的S(2-4) 作为Li-S电池中的新阴极材料.
- 电化学表征以评估特定容量,循环稳定性和速率能力.
主要成果:
- 封闭的S(2-4) 阴极有效地防止了S(8) 和S(4)(2-) 中间体之间的不利过渡.
- 基于这一概念的Li-S电池表现出高的特异性容量和良好的循环稳定性.
- 观察到更高的速率能力,表明电化学行为有所改善.
结论:
- 控制较小的中硫的含量,特别是S2~4的含量,有效地减少了Li-S电池的容量色.
- 这种方法为实现实用的高能量密度电池提供了一个有希望的途径.
- 开发的Li-S电池显示出在便携式电子产品,电动汽车和大规模储能领域的应用潜力.
相关概念视频
03:12Batteries and Fuel Cells
A battery is a galvanic cell that is used as a source of electrical power for specific applications. Modern batteries exist in a multitude of forms to accommodate various applications, from tiny button batteries such as those that power wristwatches to the very large batteries used to supply backup energy to municipal power grids. Some batteries are designed for single-use applications and cannot be recharged (primary cells), while others are based on conveniently reversible cell reactions that...
02:26Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
01:20Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
01:29Microbes and the Sulfur Cycle
Sulfur is a vital element in Earth's biogeochemical systems. It transitions through various inorganic states, including sulfate (SO₄²⁻), elemental sulfur (S⁰), and sulfide (S²⁻). Abiotic and biological mechanisms across oxic and anoxic environments intricately mediate these transformations. Sulfate, the most oxidized form of sulfur, is predominantly stored in rocks, marine sediments, and oceanic waters, acting as a long-term reservoir in the global sulfur cycle.In oxic environments,...
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
02:17Structure and Nomenclature of Thiols and Sulfides
Thiols and sulfides are sulfur analogs of alcohols and ethers, respectively, where the sulfur atom takes the place of the oxygen atom. Thus, thiols are generally represented as RSH, where R is an alkyl substituent and —SH is the functional group. On the other hand, in sulfides, the central sulfur atom is bonded to two hydrocarbon groups on either side. Depending upon the type of group, sulfides can be either symmetrical or asymmetrical. Both thiols and sulfides display a bent geometry, similar...