One-pot synthesis of polymeric LiPON

Abstract

Lithium metal is a promising anode material for high energy lithium ion batteries due to its high specific capacity. Inherent difficulties such as the chemical reactivity and dendrite growth during cycling have kept it from being operational in energy storage systems so far. One approach to overcome these challenges is the use of a stable interlayer on top of the lithium. The glassy solid-state electrolyte lithium phosphorus oxynitride (LiPON) is a promising candidate to achieve this. However, it is prepared by a time and energy consuming physical vapor deposition technique. As an alternative to this, we developed the synthesis of a modified polyphosphazene having a similar chemical formula as the glassy LiPON which allows for a large scale application of such a stable interface with an easier and cheaper processing. Following a two-step one pot synthesis starting from poly(dichlorophosphazene), this polymeric LiPON could be successfully isolated and showed solubility in different solvents which distinguishes it clearly from sputtered LiPON.