--- res: bibo_abstract: - 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.@eng bibo_authorlist: - foaf_Person: foaf_givenName: A. foaf_name: Dunst, A. foaf_surname: Dunst - foaf_Person: foaf_givenName: V. foaf_name: Epp, V. foaf_surname: Epp - foaf_Person: foaf_givenName: I. foaf_name: Hanzu, I. foaf_surname: Hanzu - foaf_Person: foaf_givenName: Stefan Alexander foaf_name: Freunberger, Stefan Alexander foaf_surname: Freunberger foaf_workInfoHomepage: http://www.librecat.org/personId=A8CA28E6-CE23-11E9-AD2D-EC27E6697425 orcid: 0000-0003-2902-5319 - foaf_Person: foaf_givenName: M. foaf_name: Wilkening, M. foaf_surname: Wilkening bibo_doi: 10.1039/c4ee00496e bibo_issue: '8' bibo_volume: 7 dct_date: 2014^xs_gYear dct_isPartOf: - http://id.crossref.org/issn/1754-5692 - http://id.crossref.org/issn/1754-5706 dct_language: eng dct_publisher: RSC@ dct_title: Short-range Li diffusion vs. long-range ionic conduction in nanocrystalline lithium peroxide Li2O2—the discharge product in lithium-air batteries@ ...