Comprehensive Investigation of Anion Species in Crystalline Li ion Conductor Li [P O N ]O (x≈1.9(3)).

The Li ion conductor Li [P O N ]O (x≈1.9) has been synthesized from P N , Li N and Li O in a Ta ampoule at 800 °C under Ar atmosphere. The cubic compound crystallizes in space group with a=12.0106(14) Å and Z=4. It contains both non-condensed [PO N ] and [PO N] tetrahedra as well as O ions, surrounded by Li ions. Charge neutrality is achieved by partial occupancy of Li positions, which was refined with neutron powder diffraction data. Measurements of the partial ionic and electronic conductivity show a total ionic conductivity of 6.6×10  S cm with an activation energy of 0.46±0.02 eV and a bulk ionic conductivity of 4×10  S cm at 25 °C, which is close to the ionic conductivity of amorphous lithium nitridophosphate. This makes Li [P O N ]O an interesting candidate for investigation of structural factors affecting ionic conductivity in lithium oxonitridophosphates.