Is Nitrogen Present in Li3N·P2S5 Solid Electrolytes Produced by Ball Milling?

Gareth O Hartley,Ziyang Ning,Gregory J Rees,Conrad Holc,Peter G Bruce,Dominic Spencer Jolly,Liyu Jin,Stefanie Zekoll,Paul Adamson,Benjamin J Bergner,Alexander T R Pateman

doi:10.1021/acs.chemmater.9b01853

Abstract

Nitrogenous solid electrolytes such as lithium phosphorus oxynitride (LiPON) have effectual interfacial compatibility with lithium metal; in part, this has enabled the development of thin-film soli...

Highlights

If flammable liquid electrolytes are to be supplanted by purportedly safer solid electrolytes (SEs) in commercial rechargeable lithium-ion batteries, the overall energy density, specific power, and lifetimes of all-solid-state cells must become competitive with current liquid-based technology
This study has shown that ball-milled Li3N·P2S5 solid electrolytes contain less nitrogen than expected because N2 gas is evolved during milling
While small amounts of residual nitrogen are detected in Li3N·P2S5 solid electrolytes after ball milling, X-ray photoelectron spectroscopy (XPS) indicates that this nitrogen is due to unreacted Li3N and is not due to the formation of a new nitrogen compound

Summary

Introduction

If flammable liquid electrolytes are to be supplanted by purportedly safer solid electrolytes (SEs) in commercial rechargeable lithium-ion batteries, the overall energy density, specific power, and lifetimes of all-solid-state cells must become competitive with current liquid-based technology. The energy density of solid-state batteries could be increased by replacing carbonaceous intercalation anodes with metallic lithium.[1,2] Many SEs are electrochemically unstable at 0 V vs Li+/Li. SEs are commonly reduced at the lithium anode interface to form stable solid electrolyte interphases (SEIs). SEIs have heterogeneous substructures that can initiate local regions of high current density during battery cycling.[3−6] Solid-state lithium metal batteries are prone to short-circuiting during cycling at high current densities due to the formation of lithium dendrites that propagate across the SE.[6−8] As such, few ceramic solid-state lithium metal batteries have been reported with good long-term cycling performance. Novel high conductivity nitrogenous ceramics capable of forming “selfhealing” nitrogen-rich passivation layers would be promising solid electrolytes for solid-state lithium metal batteries

Results

Discussion

Conclusion