Reactions in the Rechargeable Lithium–O<sub>2</sub> Battery with Alkyl Carbonate Electrolytes

Freunberger, Stefan; Chen, Yuhui; Peng, Zhangquan; Griffin, John M.; Hardwick, Laurence J.; Bardé, Fanny; Novák, Petr; Bruce, Peter G.

doi:10.1021/ja2021747

Cited by 1,232 publications

(1,404 citation statements)

References 52 publications

Supporting

Mentioning

1,316

Contrasting

Unclassified

Order By: Relevance

“…The onset of CO 2 evolution at 3.8 V is in accordance with the equilibrium potential of Reaction 1 ( E °=3.82 V vs. Li/Li + ) 4c, 6. Consistent with numerous studies, O 2 was not detected throughout charging 4c,4g,4h, 5b. H 2 and CO evolution is observed above 4.2 V during the anodic scan of the Li 2 CO 3 ‐packed electrodes, but no gas evolution is observed below 4.5 V from blank carbon black electrodes (Figure S3).…”

supporting

confidence: 90%

“…While it is clear that Li 2 CO 3 decomposition evolves CO 2 , the fate of the third O atom in CO 3 2− has been an enduring open question since no O 2 evolves, although this would be expected from the formal oxidation reaction:3e, 4c,4f–4h,4j, 5b

true 2 Li_{2} CO_{3} \to 4 Li^{+} + 4 normale^{-} + 2 CO_{2} + normalO_{2} E^{\circ} = 3.82 normalV vs . Li / Li^{+}

…”

mentioning

confidence: 99%

See 1 more Smart Citation

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

et al. 2018

Self Cite

View full text Add to dashboard Cite

Solid alkali metal carbonates are universal passivation layer components of intercalation battery materials and common side products in metal‐O2 batteries, and are believed to form and decompose reversibly in metal‐O2/CO2 cells. In these cathodes, Li2CO3 decomposes to CO2 when exposed to potentials above 3.8 V vs. Li/Li+. However, O2 evolution, as would be expected according to the decomposition reaction 2 Li2CO3→4 Li++4 e−+2 CO2+O2, is not detected. O atoms are thus unaccounted for, which was previously ascribed to unidentified parasitic reactions. Here, we show that highly reactive singlet oxygen (1O2) forms upon oxidizing Li2CO3 in an aprotic electrolyte and therefore does not evolve as O2. These results have substantial implications for the long‐term cyclability of batteries: they underpin the importance of avoiding 1O2 in metal‐O2 batteries, question the possibility of a reversible metal‐O2/CO2 battery based on a carbonate discharge product, and help explain the interfacial reactivity of transition‐metal cathodes with residual Li2CO3.

show abstract

supporting

confidence: 90%

true 2 Li_{2} CO_{3} \to 4 Li^{+} + 4 normale^{-} + 2 CO_{2} + normalO_{2} E^{\circ} = 3.82 normalV vs . Li / Li^{+}

…”

mentioning

confidence: 99%

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The excellent cycling performance of the Fe@NCNT electrode indicates the stable electrochemical behavior with reduced polarization and high rever- sibility originated from the coupling of Fe and NCNTs at molecular level. It should be noted that the cycling performance of current Li-O2 batteries is largely harmed by the decomposition of the organic electrolyte during the electrochemical reaction [8,60]. With more stable electrolyte, the lifespan of the cells with Fe@NCNT electrode may be significantly extended for practical application.…”

Section: Resultsmentioning

confidence: 99%

Long life rechargeable Li-O2 batteries enabled by enhanced charge transfer in nanocable-like Fe@N-doped carbon nanotube catalyst

Zhou

Liu

et al. 2017

Sci. China Mater.

View full text Add to dashboard Cite

Rechargeable Li-O2 batteries have attracted considerable interests because of their exceptional energy density. However, the short lifetime still remained as one of the bottle-neck obstacles for the practical application of rechargeable Li-O2 batteries. The development of efficient cathode catalyst is highly desirable to reduce the energy barrier of Li-O2 reaction and electrode failure. In this work, we report a facile strategy for the fabrication of a high-performance cathode catalyst for rechargeable Li-O2 batteries by the encapsulation of high content of active Fe nanorods into N-doped carbon nanotubes with high stability (denoted as Fe@NCNTs). First-principles calculations reveal that the synergistic charge transfer and redistribution between the interface of Fe nanorods, the CNT walls and the active N dopants greatly facilitate the chemisorption and subsequent dissociation of O2 molecules into the epoxy intermediates on the carbon surface, which benefits the uniform growth of nanosized discharge products on CNT surface and thus boosts the reversibility of Li-O2 reactions. As a result, the cathode with Fe@NCNT catalyst exhibits long cycling stability with high capacities (1000 mA h g −1 for 160 cycles and 600 mA h g −1 for 270 cycles). Based on the total mass of Fe@NCNTs + Li2O2, high gravimetric energy densities of 2120-2600 W h kg −1 can be achieved at the power densities of 50-795 W kg −1 .

show abstract

“…(1) It has been shown that superoxide reacts irreversibly with most known electrolytes 10 and it is also probably involved in the corrosion of carbon electrodes. 11 Intensive research has been done on finding alternative electrolytes and electrode materials that are resistant towards degradation by superoxide.…”

mentioning

confidence: 99%

A new method to prevent degradation of lithium–oxygen batteries: reduction of superoxide by viologen

et al. 2015

View full text Add to dashboard Cite

Lithium-oxygen battery development is hampered by degradation reactions initiated by superoxide, which is formed in the pathway of oxygen reduction to peroxide. This work demonstrates that the superoxide lifetime is drastically decreased upon addition of ethyl viologen, which catalyses the reduction of superoxide to peroxide.Lithium-oxygen batteries can potentially deliver 5 times more energy than lithium-ion batteries of the same weight. [1][2][3][4][5][6][7] The energy is provided by the electrochemical reaction between Li and O2, typically forming Li2O2. Since all these compounds are very light, the mass of the battery can be very small, leading to a high specific energy (i.e. energy per mass). However, several factors hamper the practical performance of current lithium-oxygen batteries. First of all, superoxide is formed as the first product of the reduction of O2: 8,9 O2 + e -+Li + → LiO2(1) It has been shown that superoxide reacts irreversibly with most known electrolytes 10 and it is also probably involved in the corrosion of carbon electrodes. 11 Intensive research has been done on finding alternative electrolytes and electrode materials that are resistant towards degradation by superoxide. A few solvents like dimethyl sulfoxide 12 , some glymes 13, 14 and pyrrolidinium or piperidinium based ionic liquids [15][16][17][18][19] have been identified as promising electrolyte choices. Gold 12 and TiC 20 electrodes have shown much better capacity performance than carbon, in terms of cycling stability and suppression of side reactions. An alternative approach to solve the superoxide problem is the introduction of catalysts to promote the reduction of superoxide to peroxide: LiO2 + e -+Li + → Li2O2(2) This would decrease the lifetime of superoxide and, with this, the long-term durability of the battery. If the superoxide lifetime were short enough, it would be conceivable that a wider range of materials could be incorporated in lithium-oxygen batteries without serious problems of degradation reactions. In addition, such catalysts would also be beneficial in order to speed up the overall 2-electron reduction of oxygen to Li2O2. In the absence of such catalyst, Li2O2 is usually formed by disproportionation of LiO2: 8, 9 2LiO2 →O2+ Li2O2 (3) However, as will be shown below, the rate of this reaction is very slow at low superoxide concentrations. Another important issue in lithium-oxygen batteries is that the discharge product, Li2O2, deposits on the surface of the electrode, blocking its electrochemical activity. This produces a very early end of discharge, with little discharge product being formed, and little capacity being delivered. An innovative solution to solve this problem is the introduction of soluble redox shuttles that can displace the formation of Li2O2 from the electrode surface to the solution, by reducing oxygen through a homogenous chemical reaction. 21,22 Soluble redox couples have also been used as mediators for the evolution of oxygen in lithium-oxygen batteries, resulting in major performance i...

show abstract

Reactions in the Rechargeable Lithium–O₂ Battery with Alkyl Carbonate Electrolytes

Cited by 1,232 publications

References 52 publications

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

Long life rechargeable Li-O2 batteries enabled by enhanced charge transfer in nanocable-like Fe@N-doped carbon nanotube catalyst

A new method to prevent degradation of lithium–oxygen batteries: reduction of superoxide by viologen

Contact Info

Product

Resources

About

Reactions in the Rechargeable Lithium–O2 Battery with Alkyl Carbonate Electrolytes

Cited by 1,232 publications

References 52 publications

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen

Long life rechargeable Li-O2 batteries enabled by enhanced charge transfer in nanocable-like Fe@N-doped carbon nanotube catalyst

A new method to prevent degradation of lithium–oxygen batteries: reduction of superoxide by viologen

Contact Info

Product

Resources

About

Reactions in the Rechargeable Lithium–O₂ Battery with Alkyl Carbonate Electrolytes