Work

Origin of Stability in the Solid Electrolyte Interphase formed between Lithium and Lithium Phosphorus Oxynitride

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Lithium phosphorus oxynitride (LiPON) is one of the few solid electrolytes that form a truly passivating solid electrolyte interphase (SEI) when in contact with metallic lithium. Investigations into the origin of this stability may provide the insights needed to replicate it in the SEIs of alternative solid electrolyte materials. In this study, we used in situ lithium plating X-ray photoelectron spectroscopy (XPS) to investigate the formation and evolution of the Li-LiPON SEI. We show that the SEI is chemically and structurally inhomogeneous, with the fully reduced compounds identified in previous studies (Li 2 O, Li 3 N, and Li 3 P) concentrated near the lithium metal side and partially lithiated species, including Li x P, predominant closer to the LiPON side. Li 3 P and Li x P have recently been suggested as enablers of continuous SEI growth in thiophosphate solid electrolytes. We suggest that the stability of the Li-LiPON SEI is derived from a combination of the LiPON reduction potential (0.68 V vs Li + /Li), which is below the oxidation potentials of the fully reduced SEI compounds, and the graded structure of the SEI, which ensures that the most reduced species are not in physical or electrical contact with the LiPON layer.

Source: Chemistry of Materials

DOI: 10.1021/acs.chemmater.5c00483

Authors: Stephen J. Turrell, Yi Liang, Tiancheng Cai, Ben Jagger, Mauro Pasta

Institutions: University of Oxford, The Faraday Institution

Language: English

Topic: Advanced Battery Materials and Technologies

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Henry Royce Institute, Faraday Institution, Clarendon Fund