Spatial Distributions of Discharged Products of Lithium-Oxygen Batteries Revealed by Synchrotron X-ray Transmission Microscopy.
The discharge products of ether-based Li-O2 cells were grown directly on common carbon-coated TEM grids and observed by oxidation-state-sensitive full field transmission soft X-ray microscopy (TXM). The acquired data have permitted to quantify and localize with spatial resolution the distribution of the oxygen discharge products in these samples (i.e., lithium superoxide, peroxide, and carbonates) and appreciate several compositional, structural, and morphological aspects. Most of the peroxide particles had a toroidal shape, often with a central hole usually open on only one side, and which included significant amounts of superoxide-like phases (LiO2/Li2O2 ratio between 0.2 and 0.5). Smaller particles had smaller or no superoxide content, from which we infer that abundance of soluble LiO2 may have a role in toroid formation. Significant amount of carbonates were found irregularly distributed on the electrode surface, occasionally appearing as small particles and aggregates, and mostly coating lithium peroxide particles. This suggests the formation of a barrier that, similar to the solid electrolyte interface (SEI) critical in Li-ion batteries, requires an appropriate management for a reversible operation.
Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC) , Campus UAB, ES 08193 Bellaterra, Barcelona, Spain.
Mara
M
Olivares-Marín
ALBA Synchrotron Light Source, MISTRAL Beamline-Experiments Division , 08290 Cerdanyola del Vallès, Barcelona, Spain.
Andrea
A
Sorrentino
Department of Chemical Engineering, National Taiwan University , Taipei 10617, Taiwan.
Rung-Chuan
RC
Lee
ALBA Synchrotron Light Source, MISTRAL Beamline-Experiments Division , 08290 Cerdanyola del Vallès, Barcelona, Spain.
Eva
E
Pereiro
Department of Chemical Engineering, National Taiwan University , Taipei 10617, Taiwan.
Nae-Lih
NL
Wu
Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC) , Campus UAB, ES 08193 Bellaterra, Barcelona, Spain.
Dino
D
Tonti
D011211:Electric Power Supplies; D008094:Lithium / Q000737:chemistry*; D008854:Microscopy, Electron / Q000379:methods*; D010100:Oxygen / Q000737:chemistry*; D017356:Synchrotrons
D008094:Lithium; D010100:Oxygen
Li2O2; LiO2; Lithium−oxygen batteries; soft X-ray microscopy; toroids