A Solvent-Controlled Oxidation Mechanism of Li2O2 in Lithium-Oxygen Batteries

Yu, Weichao; Lai, Nien-Chu; Lu, Ying‐Rui; Zhou, Yucun; Dong, Chung‐Li; Lu, Yi-Chun

doi:10.1016/j.joule.2018.07.021

Cited by 169 publications

(210 citation statements)

References 96 publications

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“…The homogenous formation of Li 2 O 2 was also investigated using the RRDE by analyzing the rotational dependency of the collection efficiency . In more recent work in the field of metal‐air batteries with a RRDE even the evolution of superoxide during charge was reported . In these experiments, we used KClO 4 and LiClO 4 supporting salts in a TEGDME based electrolyte.…”

Section: Resultsmentioning

confidence: 99%

“…A detailed description of our reference electrode used for the DEMS measurements can be found elsewhere . The potential of the Ag + |Ag reference in acetonitrile was calibrated against Li metal in DMSO and TEGDME . On this basis and with the listed values of Ag + |Ag values we calculated our reference potential with −3.198 V vs Li + |Li in TEGDME and −3.742 V in DMSO.…”

Section: Methodsmentioning

confidence: 99%

“…[30] The potential of the Ag + j Ag reference in acetonitrile was calibrated against Li metal in DMSO and TEGDME. [31] On this basis and with the listed values [32] of Ag + j Ag values we calculated our reference potential with À 3.198 V vs Li + j Li in TEGDME and À 3.742 V in DMSO. A sketch towards the calculation of the reference potential is given in the supporting information.…”

Section: Reference Electrodementioning

confidence: 99%

“…[33,34,44] In more recent work in the field of metal-air batteries with a RRDE even the evolution of superoxide during charge was reported. [31,45,46] In these experiments, we used KClO 4 and LiClO 4 supporting salts in a TEGDME based electrolyte. The experimental data in oxygen containing electrolyte is shown in Figure 6.…”

Section: Electrochemical Studies In Tegdme-based Electrolytesmentioning

confidence: 99%

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Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association

2019

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One of the bottlenecks in Li−O2 batteries is the film like growth of Li2O2 on the electrode surface during discharge leading to early cell death. To tackle this problem 2,5‐Di‐tert‐1,4‐benzoquinone (DBBQ) was introduced as a soluble redox mediator. This redox mediator is avoiding the Li2O2 layer‐by‐layer growth on the electrode surface and thus leading to higher discharge capacities of the Li−O2 cell. In this study, we investigate the ion pairing between the cation of the conducting salt and the DBBQ monoanion and the resulting impact on the ORR activity of the DBBQ monoanion. We investigate TBA+, K+ and Li+ as cations and TEGDME and DMSO as solvents. We found out that there is a direct correlation between the ORR activity of DBBQ− and the ion pairing of DBBQ− with the cation of the supporting electrolyte: Only if DBBQ is strongly associated with the cations of the electrolyte it will reduce oxygen in the electrolyte. Increasing the Li+ concentration in the electrolyte shifts the ORR potential to more positive electrode potentials. In addition, we are describing a new experimental approach to investigate the kinetics of the homogenous ORR via time resolved mass spectrometry. With this approach we found out, that the reaction Li··· DBBQ(sol)+O2(sol)↔k-1k1 Li··· DBBQ··· O2(sol) is 80 times faster in a TEGDME based electrolyte than in a DMSO‐based electrolyte. We determined k1 with 5.1· 102 s−1 M−1and k-1 with 3.7 102 s−1 M−1 in TEGDME whereas the constants in DMSO are k1 =4.5 s−1 M−1 and k-1 =5.5 s−1 M−1s.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Reference Electrodementioning

confidence: 99%

Section: Electrochemical Studies In Tegdme-based Electrolytesmentioning

confidence: 99%

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Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association

2019

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“…However, such testing conditions could not fully reconstruct the situation of Li-O 2 batteries under real operation [33]. Later on, Lu et al [34] proposed that the oxidation mechanism of Li 2 O 2 is closely related to the DN of electrolyte solvent. Through rotating ring-disk electrode (RRDE) and X-ray absorption near-edge structure, they confirmed the different OER mechanisms of Li-O 2 batteries using different solvent varied in DN as described in Figure 1d.…”

Section: Overview Of Li-o 2 Batteriesmentioning

confidence: 99%

Recent Progress on Catalysts for the Positive Electrode of Aprotic Lithium-Oxygen Batteries †

2019

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Rechargeable aprotic lithium-oxygen (Li-O2) batteries have attracted significant interest in recent years owing to their ultrahigh theoretical capacity, low cost, and environmental friendliness. However, the further development of Li-O2 batteries is hindered by some ineluctable issues, such as severe parasitic reactions, low energy efficiency, poor rate capability, short cycling life and potential safety hazards, which mainly stem from the high charging overpotential in the positive electrode side. Thus, it is of great significance to develop high-performance catalysts for the positive electrode in order to address these issues and to boost the commercialization of Li-O2 batteries. In this review, three main categories of catalyst for the positive electrode of Li-O2 batteries, including carbon materials, noble metals and their oxides, and transition metals and their oxides, are systematically summarized and discussed. We not only focus on the electrochemical performance of batteries, but also pay more attention to understanding the catalytic mechanism of these catalysts for the positive electrode. In closing, opportunities for the design of better catalysts for the positive electrode of high-performance Li-O2 batteries are discussed.

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Lithium–Oxygen Batteries

Petit

Mourad

Freunberger

2020

Encyclopedia of Electrochemistry

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Rechargeable Li–O 2 batteries have gathered enormous attention in the research community for having amongst the highest theoretical energy storage. Realizing the promise, even in part, in practice could produce a device that stores significantly more energy than other rechargeable batteries. Fundamental understanding of the reaction mechanisms is now realized to be key to overcome many challenges. We give a critical overview of the current understanding of the chemistry underpinning the Li–O 2 cell with focus on the cathode and give a perspective on the most important research needs. Since performance and reversibility are often grossly misunderstood, we put emphasis on realistic performances to be achieved by Li–O 2 cells and on means to identify reversibility. Parasitic chemistry is the foremost barrier for reversible cycling and now realized to be predominantly caused by singlet oxygen rather than by the previously thought superoxide or peroxide. This finding profoundly affects any other area of research from reaction mechanisms, to electrolytes and catalysts and dominates future research needs.

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A Solvent-Controlled Oxidation Mechanism of Li2O2 in Lithium-Oxygen Batteries

Cited by 169 publications

References 96 publications

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association

Recent Progress on Catalysts for the Positive Electrode of Aprotic Lithium-Oxygen Batteries †

Lithium–Oxygen Batteries

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A Solvent-Controlled Oxidation Mechanism of Li2O2 in Lithium-Oxygen Batteries

Cited by 169 publications

References 96 publications

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O2 Batteries: The Importance of Ion Association

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O2 Batteries: The Importance of Ion Association

Recent Progress on Catalysts for the Positive Electrode of Aprotic Lithium-Oxygen Batteries †

Lithium–Oxygen Batteries

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Product

Resources

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Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O₂ Batteries: The Importance of Ion Association