可充电-O2电池与碳酸电解质的反应
Stefan A Freunberger1, Yuhui Chen, Zhangquan Peng
1School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK.
Journal of the American Chemical Society
|April 29, 2011
概括
非水性-O(2) 电池在放电和充电过程中分解碳酸电解质,形成导致容量衰减的固体产品. 这种电解质分解限制了这些先进的储能系统的循环寿命.
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
- 储能 储能 储能 储能 储能 储能
背景情况:
- 非水性可充电O2电池具有较高的理论能量密度.
- 电解质分解是一个主要的挑战,限制了它们的实际应用和循环寿命.
研究的目的:
- 阐明在Li-O(2) 电池中充电和放电周期期间电解质分解的特定机制.
- 为了识别形成的化学物种及其对电池性能的影响.
主要方法:
- 分析在放电过程中形成的正极产物.
- 在循环过程中对阳极表面变化的研究.
- 为充电和放电过程提出反应机制.
主要成果:
- 排放的形式是C(3)H(6)(OCO(2)Li)(2),Li(2)CO(3),HCO(2)Li,CH(3)CO(2)Li,CO(2) 和 H(2)O 在阴极上.
- 充电涉及这些物种与CO2和H2O进化的氧化.
- 电解质分解导致固体产品的积累,阳极上的凝形成,容量衰减和细胞衰竭.
结论:
- 提出的反应机制解释了Li-O(2) 细胞中观察到的电压差距.
- 持续的电解质消耗和产品积累是导致容量衰减和周期寿命有限的主要原因.
- 解决电解质稳定性对于开发实用的Li-O(2) 电池至关重要.
相关概念视频
Batteries 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...
Electrolysis
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...
Acid Halides to Alcohols: LiAlH4 Reduction
Acid halides are reduced to alcohols in the presence of a strong reducing agent like lithium aluminum hydride.
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...
α-Alkylation of Ketones via Enolate Ions
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the strong interaction...
Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
Baeyer–Villiger oxidation converts aldehydes to carboxylic acids and ketones to esters. The reaction uses peroxy acids or peracids and is often catalyzed by acid. The reaction is named after its pioneers, Adolf von Baeyer and Victor Villiger. The reaction is achieved by a wide range of peracids such as m-chloroperoxybenzoic acid (mCPBA), perbenzoic acid (C6H5COOOH), peracetic acid (CH3COOOH), hydrogen peroxide (H2O2), and tert-butyl hydroperoxide (t-BuOOH).
The carbonyl center is activated by...
The carbonyl center is activated by...


