---
_id: '7275'
abstract:
- lang: eng
  text: Aprotic alkali metal–oxygen batteries require reversible formation of metal
    superoxide or peroxide on cycling. Severe parasitic reactions cause poor rechargeability,
    efficiency, and cycle life and have been shown to be caused by singlet oxygen
    (1O2) that forms at all stages of cycling. However, its formation mechanism remains
    unclear. We show that disproportionation of superoxide, the product or intermediate
    on discharge and charge, to peroxide and oxygen is responsible for 1O2 formation.
    While the overall reaction is driven by the stability of peroxide and thus favored
    by stronger Lewis acidic cations such as Li+, the 1O2 fraction is enhanced by
    weak Lewis acids such as organic cations. Concurrently, the metal peroxide yield
    drops with increasing 1O2. The results explain a major parasitic pathway during
    cell cycling and the growing severity in K–, Na–, and Li–O2 cells based on the
    growing propensity for disproportionation. High capacities and rates with peroxides
    are now realized to require solution processes, which form peroxide or release
    O2via disproportionation. The results therefore establish the central dilemma
    that disproportionation is required for high capacity but also responsible for
    irreversible reactions. Highly reversible cell operation requires hence finding
    reaction routes that avoid disproportionation.
article_processing_charge: No
article_type: original
author:
- first_name: Eléonore
  full_name: Mourad, Eléonore
  last_name: Mourad
- first_name: Yann K.
  full_name: Petit, Yann K.
  last_name: Petit
- first_name: Riccardo
  full_name: Spezia, Riccardo
  last_name: Spezia
- first_name: Aleksej
  full_name: Samojlov, Aleksej
  last_name: Samojlov
- first_name: Francesco F.
  full_name: Summa, Francesco F.
  last_name: Summa
- first_name: Christian
  full_name: Prehal, Christian
  last_name: Prehal
- first_name: Christian
  full_name: Leypold, Christian
  last_name: Leypold
- first_name: Nika
  full_name: Mahne, Nika
  last_name: Mahne
- first_name: Christian
  full_name: Slugovc, Christian
  last_name: Slugovc
- first_name: Olivier
  full_name: Fontaine, Olivier
  last_name: Fontaine
- first_name: Sergio
  full_name: Brutti, Sergio
  last_name: Brutti
- first_name: Stefan Alexander
  full_name: Freunberger, Stefan Alexander
  id: A8CA28E6-CE23-11E9-AD2D-EC27E6697425
  last_name: Freunberger
  orcid: 0000-0003-2902-5319
citation:
  ama: Mourad E, Petit YK, Spezia R, et al. Singlet oxygen from cation driven superoxide
    disproportionation and consequences for aprotic metal–O2 batteries. <i>Energy
    &#38; Environmental Science</i>. 2019;12(8):2559-2568. doi:<a href="https://doi.org/10.1039/c9ee01453e">10.1039/c9ee01453e</a>
  apa: Mourad, E., Petit, Y. K., Spezia, R., Samojlov, A., Summa, F. F., Prehal, C.,
    … Freunberger, S. A. (2019). Singlet oxygen from cation driven superoxide disproportionation
    and consequences for aprotic metal–O2 batteries. <i>Energy &#38; Environmental
    Science</i>. RSC. <a href="https://doi.org/10.1039/c9ee01453e">https://doi.org/10.1039/c9ee01453e</a>
  chicago: Mourad, Eléonore, Yann K. Petit, Riccardo Spezia, Aleksej Samojlov, Francesco
    F. Summa, Christian Prehal, Christian Leypold, et al. “Singlet Oxygen from Cation
    Driven Superoxide Disproportionation and Consequences for Aprotic Metal–O2 Batteries.”
    <i>Energy &#38; Environmental Science</i>. RSC, 2019. <a href="https://doi.org/10.1039/c9ee01453e">https://doi.org/10.1039/c9ee01453e</a>.
  ieee: E. Mourad <i>et al.</i>, “Singlet oxygen from cation driven superoxide disproportionation
    and consequences for aprotic metal–O2 batteries,” <i>Energy &#38; Environmental
    Science</i>, vol. 12, no. 8. RSC, pp. 2559–2568, 2019.
  ista: Mourad E, Petit YK, Spezia R, Samojlov A, Summa FF, Prehal C, Leypold C, Mahne
    N, Slugovc C, Fontaine O, Brutti S, Freunberger SA. 2019. Singlet oxygen from
    cation driven superoxide disproportionation and consequences for aprotic metal–O2
    batteries. Energy &#38; Environmental Science. 12(8), 2559–2568.
  mla: Mourad, Eléonore, et al. “Singlet Oxygen from Cation Driven Superoxide Disproportionation
    and Consequences for Aprotic Metal–O2 Batteries.” <i>Energy &#38; Environmental
    Science</i>, vol. 12, no. 8, RSC, 2019, pp. 2559–68, doi:<a href="https://doi.org/10.1039/c9ee01453e">10.1039/c9ee01453e</a>.
  short: E. Mourad, Y.K. Petit, R. Spezia, A. Samojlov, F.F. Summa, C. Prehal, C.
    Leypold, N. Mahne, C. Slugovc, O. Fontaine, S. Brutti, S.A. Freunberger, Energy
    &#38; Environmental Science 12 (2019) 2559–2568.
date_created: 2020-01-15T07:18:04Z
date_published: 2019-08-01T00:00:00Z
date_updated: 2021-01-12T08:12:41Z
day: '01'
ddc:
- '530'
- '541'
- '540'
doi: 10.1039/c9ee01453e
extern: '1'
file:
- access_level: open_access
  checksum: 94d4cfb2ab0b4c90ef76a7f3cc811feb
  content_type: application/pdf
  creator: dernst
  date_created: 2020-01-30T16:11:05Z
  date_updated: 2020-07-14T12:47:55Z
  file_id: '7424'
  file_name: 2019_EnergyEnvironScienc_Mourad.pdf
  file_size: 2888027
  relation: main_file
file_date_updated: 2020-07-14T12:47:55Z
has_accepted_license: '1'
intvolume: '        12'
issue: '8'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc/4.0/
month: '08'
oa: 1
oa_version: Published Version
page: 2559-2568
publication: Energy & Environmental Science
publication_identifier:
  issn:
  - 1754-5692
  - 1754-5706
publication_status: published
publisher: RSC
quality_controlled: '1'
status: public
title: Singlet oxygen from cation driven superoxide disproportionation and consequences
  for aprotic metal–O2 batteries
tmp:
  image: /images/cc_by_nc.png
  legal_code_url: https://creativecommons.org/licenses/by-nc/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
  short: CC BY-NC (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 12
year: '2019'
...
---
_id: '7302'
abstract:
- lang: eng
  text: Understanding charge carrier transport in Li2O2, the storage material in the
    non-aqueous Li-O2 battery, is key to the development of this high-energy battery.
    Here, we studied ionic transport properties and Li self-diffusion in nanocrystalline
    Li2O2 by conductivity and temperature variable 7Li NMR spectroscopy. Nanostructured
    Li2O2, characterized by a mean crystallite size of less than 50 nm as estimated
    from X-ray diffraction peak broadening, was prepared by high-energy ball milling
    of microcrystalline lithium peroxide with μm sized crystallites. At room temperature
    the overall conductivity σ of the microcrystalline reference sample turned out
    to be very low (3.4 × 10−13 S cm−1) which is in agreement with results from temperature-variable
    7Li NMR line shape measurements. Ball-milling, however, leads to an increase of
    σ by approximately two orders of magnitude (1.1 × 10−10 S cm−1); correspondingly,
    the activation energy decreases from 0.89 eV to 0.82 eV. The electronic contribution
    σeon, however, is in the order of 9 × 10−12 S cm−1 which makes less than 10% of
    the total value. Interestingly, 7Li NMR lines of nano-Li2O2 undergo pronounced
    heterogeneous motional narrowing which manifests in a two-component line shape
    emerging with increasing temperatures. Most likely, the enhancement in σ can be
    traced back to the generation of a spin reservoir with highly mobile Li ions;
    these are expected to reside in the nearest neighbourhood of defects generated
    or near the structurally disordered and defect-rich interfacial regions formed
    during mechanical treatment.
article_processing_charge: No
article_type: original
author:
- first_name: A.
  full_name: Dunst, A.
  last_name: Dunst
- first_name: V.
  full_name: Epp, V.
  last_name: Epp
- first_name: I.
  full_name: Hanzu, I.
  last_name: Hanzu
- first_name: Stefan Alexander
  full_name: Freunberger, Stefan Alexander
  id: A8CA28E6-CE23-11E9-AD2D-EC27E6697425
  last_name: Freunberger
  orcid: 0000-0003-2902-5319
- first_name: M.
  full_name: Wilkening, M.
  last_name: Wilkening
citation:
  ama: Dunst A, Epp V, Hanzu I, Freunberger SA, Wilkening M. Short-range Li diffusion
    vs. long-range ionic conduction in nanocrystalline lithium peroxide Li2O2—the
    discharge product in lithium-air batteries. <i>Energy &#38; Environmental Science</i>.
    2014;7(8):2739-2752. doi:<a href="https://doi.org/10.1039/c4ee00496e">10.1039/c4ee00496e</a>
  apa: Dunst, A., Epp, V., Hanzu, I., Freunberger, S. A., &#38; Wilkening, M. (2014).
    Short-range Li diffusion vs. long-range ionic conduction in nanocrystalline lithium
    peroxide Li2O2—the discharge product in lithium-air batteries. <i>Energy &#38;
    Environmental Science</i>. RSC. <a href="https://doi.org/10.1039/c4ee00496e">https://doi.org/10.1039/c4ee00496e</a>
  chicago: Dunst, A., V. Epp, I. Hanzu, Stefan Alexander Freunberger, and M. Wilkening.
    “Short-Range Li Diffusion vs. Long-Range Ionic Conduction in Nanocrystalline Lithium
    Peroxide Li2O2—the Discharge Product in Lithium-Air Batteries.” <i>Energy &#38;
    Environmental Science</i>. RSC, 2014. <a href="https://doi.org/10.1039/c4ee00496e">https://doi.org/10.1039/c4ee00496e</a>.
  ieee: A. Dunst, V. Epp, I. Hanzu, S. A. Freunberger, and M. Wilkening, “Short-range
    Li diffusion vs. long-range ionic conduction in nanocrystalline lithium peroxide
    Li2O2—the discharge product in lithium-air batteries,” <i>Energy &#38; Environmental
    Science</i>, vol. 7, no. 8. RSC, pp. 2739–2752, 2014.
  ista: Dunst A, Epp V, Hanzu I, Freunberger SA, Wilkening M. 2014. Short-range Li
    diffusion vs. long-range ionic conduction in nanocrystalline lithium peroxide
    Li2O2—the discharge product in lithium-air batteries. Energy &#38; Environmental
    Science. 7(8), 2739–2752.
  mla: Dunst, A., et al. “Short-Range Li Diffusion vs. Long-Range Ionic Conduction
    in Nanocrystalline Lithium Peroxide Li2O2—the Discharge Product in Lithium-Air
    Batteries.” <i>Energy &#38; Environmental Science</i>, vol. 7, no. 8, RSC, 2014,
    pp. 2739–52, doi:<a href="https://doi.org/10.1039/c4ee00496e">10.1039/c4ee00496e</a>.
  short: A. Dunst, V. Epp, I. Hanzu, S.A. Freunberger, M. Wilkening, Energy &#38;
    Environmental Science 7 (2014) 2739–2752.
date_created: 2020-01-15T12:17:43Z
date_published: 2014-08-01T00:00:00Z
date_updated: 2021-01-12T08:12:53Z
day: '01'
doi: 10.1039/c4ee00496e
extern: '1'
intvolume: '         7'
issue: '8'
language:
- iso: eng
month: '08'
oa_version: Published Version
page: 2739-2752
publication: Energy & Environmental Science
publication_identifier:
  issn:
  - 1754-5692
  - 1754-5706
publication_status: published
publisher: RSC
quality_controlled: '1'
status: public
title: Short-range Li diffusion vs. long-range ionic conduction in nanocrystalline
  lithium peroxide Li2O2—the discharge product in lithium-air batteries
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 7
year: '2014'
...