The role of phosphorus in the solid electrolyte interphase of argyrodite solid electrolytes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41120296.
- Also identified by DOI 10.1038/s41467-025-64357-3 and PMC identifier 12540886.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The solid electrolyte interphase that forms on Li<sub>6</sub>PS<sub>5</sub>Cl argyrodite solid electrolytes has been reported to continually grow through a diffusion-controlled process, yet this process is not fully understood. Here, we use a combination of electrochemical and X-ray photoelectron spectroscopy techniques to elucidate the role of phosphorus in this growth mechanism. We uncover how Li<sub>6</sub>PS<sub>5</sub>Cl can decompose at potentials well above the full reduction to Li<sub>3</sub>P, forming partially lithiated phosphorus species, Li<sub>x</sub>P. We provide evidence of a gradient of Li<sub>x</sub>P species throughout the solid electrolyte interphase and propose a growth mechanism in which the rate-determining step is the diffusion of lithium through Li<sub>x</sub>P. We predict continuous solid electrolyte interphase growth as long as metallic lithium is present and a Li<sub>x</sub>P percolation pathway exists, highlighting the importance of understanding and engineering solid electrolyte interphase composition and nanostructure in solid-state batteries. We believe that this growth mechanism would apply to any solid electrolyte interphase that can contain partially lithiated phosphorus, or potentially any lithium alloy.