Computational Investigation of the Electrolyte Properties of Li12P3N9 and Its High Pressure Polymorph Li4PN3 through First-Principles Simulations

Abstract

Two recently synthesized crystalline materials which belong to the LiPON materials family, Li12P3N9 and it’s high–pressure polymorph Li4PN3, have been computationally examined as solid electrolytes for the usage in Li–ion batteries through first–principles simulations. The simulations of the idealized electrolyte properties of both materials suggests that these materials are promising solid electrolytes. The simulated crystal structures of both materials found to be in good agreement with experimental data, the phase transition between Li12P3N9 and Li4PN3 at high pressure has been validated through the simulations and found to be consistent with computational and experimental literature. The Li–ion migration analysis predicts that these materials are a very promising conductors for Li–ions with a calculated value for the activation energy comparable and even smaller to those of good solid electrolytes in the same materials family. The Li–ion migration analysis also suggests that the Li–ion migration is dominated with the vacancy migration mechanism which takes place along the three diffusion axes in Li12P3N4 and along the c–axis only in Li4PN3. The simulations of idealized interfaces with metallic Li anode demonstrate that these materials are likely to form a metastable interfaces with Li metal.