Structure Determination of the Crystalline LiPON Model Structure Li P O N with x≈0.9.

Non-crystalline lithium oxonitridophosphate (LiPON) is used as solid electrolyte in all-solid-state batteries. Crystalline lithium oxonitridophosphates are important model structures to retrieve analytical information that can be used to understand amorphous phases better. The new crystalline lithium oxonitridophosphate Li P O N was synthesized as an off-white powder by ampoule synthesis at 750-800 °C under Ar atmosphere. It crystallizes in the monoclinic space group P2 /c with a=15.13087(11) Å, b=9.70682(9) Å, c=8.88681(7) Å, and β=106.8653(8)°. Two P(O,N) tetrahedra connected by an N atom form the structural motif [P O N ] . The structure was elucidated from X-ray diffraction data and the model corroborated by NMR and infrared spectroscopy, and elemental analyses. Measurements of ionic conductivity show a total ionic conductivity of 6.8×10  S cm at 75 °C with an activation energy of 0.52±0.01 eV.