Multi-ion Conduction in Li3OCl Glass Electrolytes

Authors: 
Hendrik H. Heenen, Johannes Voss, Christoph Scheurer, Karsten Reuter, Alan C. Luntz
Year of publication: 
2019
Journal: 
Journal of Physical Chemistry Letters

Antiperovskite glasses such as Li3OCl and doped analogues have been proposed as excellent electrolytes for all-solid-state Li ion batteries (ASSB). Incorporating these electrolytes in ASSBs results in puzzling properties. This Letter describes a theoretical Li3OCl glass created by conventional melt–quench procedures. The ion conductivities are calculated using molecular dynamics based on a polarizable force field that is fitted to an extensive set of density functional theory-based energies, forces, and stresses for a wide range of nonequilibrium structures encompassing crystal, glass, and melt. We find high Li+ ion conductivity in good agreement with experiments. However, we also find that the Cl ion is mobile as well so that the Li3OCl glass is not a single-ion conductor, with a transference number t+ ≈ 0.84. This has important implications for its use as an electrolyte for all-solid-state batteries because the Cl could react irreversibly with the electrodes and/or produce glass decomposition during discharge–charge.

Research Areas: 
Funding sources: