Structure Determination of the Crystalline LiPON Model Structure Li5+xP2O6-xN1+x 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 Li5+xP2O6-xN1+x was synthesized as an off-white powder by ampoule synthesis at 750-800 degrees C under Ar atmosphere. It crystallizes in the monoclinic space group P2(1)/c with a=15.13087(11) angstrom, b=9.70682(9) angstrom, c=8.88681(7) angstrom, and beta=106.8653(8)degrees. Two P(O,N)(4) tetrahedra connected by an N atom form the structural motif [P2O6-xN1+x]((5+x)-). 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 6.8x10(-7) S cm(-1) at 75 degrees C with an activation energy of 0.52 +/- 0.01 eV.

Automated summary

A new crystalline lithium oxonitridophosphate with a structural motif of two P(O,N)(4) tetrahedra connected by an N atom has been synthesized and characterized. Its structure was determined by X-ray diffraction and corroborated by NMR, infrared spectroscopy, and elemental analyses. The new compound exhibits high ionic conductivity at low temperature.