在4.5V的氧化阴极中,渐变和脱离集群的阳离子还原启用了不可检测的O2形成
Na Li1,2, Enyue Zhao1, Zhigang Zhang1
1Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
Advanced materials (Deerfield Beach, Fla.)
|October 14, 2024
概括
这项研究引入了一种新的晶体结构设计,以防止在阴极材料中的阴离子氧化还原反应期间释放氧气. 这一突破提高了先进电池应用的能量密度和结构稳定性.
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:
- 氧化阴极中的阳离子氧化还原化学提供了更高的能量密度,但受到有害的氧气 (O2) 形成的阻碍.
- 氧气释放会破坏材料结构的稳定,限制电池性能和循环寿命.
- 现有的策略难以在阳离子还氧化过程中减轻O2演变.
研究的目的:
- 设计和验证一种在离子氧化还原反应中抑制O2形成的晶体结构.
- 为了提高离子电池阴极材料的能量密度和结构完整性.
- 为了克服当前氧化阴极中的阳离子氧化还原方法的局限性.
主要方法:
- 制造P2类型的基于酸的分层氧化物,具有梯度氧化还原活性和脱集群氧.
- 运行微分电化学质谱 (DEMS) 和外置50K电子磁共振 (EPR) 来检测O2.
- 现场X射线衍射 (XRD),现场中子衍射,以及分析结构变化和离子迁移的理论计算.
主要成果:
- 在设计的阴极材料中证明没有自由或被困的O2释放.
- 达到247mA hg-1的高可逆容量和优异的容量保留 (91.4%在300个周期后).
- 观察到最小的格子体积变化 (0.5%) 和由于抑制的O2形成而抑制的P2-O2相变.
结论:
- 晶体结构设计有效地防止了O2的形成,解决了阴离子氧化还原阴极的一个关键挑战.
- 该材料表现出优异的电化学性能和结构稳定性,为高能量密度电池铺平了道路.
- 减少了阴离子迁移和保持了晶格秩序,有助于增强循环稳定性.
相关概念视频
Voltaic/Galvanic Cells
56.8K
Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
56.8K
Electrodeposition
607
Electrodeposition is a technique used to separate an analyte from interferents by electrochemical processes. Here, the analyte is a metal ion that can be deposited on an electrode immersed in the sample solution. The electrochemical setup consists of an anode and a cathode. When an electric current is applied to the setup, oxidation occurs at the anode. At the cathode, which consists of a large metal surface, metal ions undergo reduction and deposit onto the surface.
Electrodeposition can...
Electrodeposition can...
607
Ladder Diagrams: Redox Equilibria
443
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
443
Balancing Redox Equations
51.8K
Electrochemistry is the science involved in the interconversion of electrical and chemical reactions. Such reactions are called reduction-oxidation, or redox reactions. These important reactions are defined by changes in oxidation states for one or more reactant elements and include a subset of reactions involving the transfer of electrons between reactant species. Electrochemistry as a field has evolved to yield sufficient insights on the fundamental principles of redox chemistry and multiple...
51.8K
Electrolysis
26.1K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.1K
Oxidation Numbers
36.9K
In redox reactions, the transfer of electrons occurs between reacting species. Electron transfer is described by a hypothetical number called the oxidation number (or oxidation state). It represents the effective charge of an atom or element, which is assigned using a set of rules.
36.9K


