A free-standing lithium phosphorus oxynitride thin film electrolyte promotes uniformly dense lithium metal deposition with no external pressure

Lithium phosphorus oxynitride (LiPON) is an amorphous solid electrolyte that has been extensively studied over the last three decades. Despite the promise of pairing it with various electrode materials, LiPON's rigidity and air sensitivity set limitations to understanding its intrinsic properties. Here we report a methodology to synthesize LiPON in a free-standing form that manifests remarkable flexibility and a Young's modulus of & SIM;33 GPa. We use solid-state nuclear magnetic resonance and differential scanning calorimetry to quantitatively reveal the chemistry of the Li/LiPON interface and the presence of a well-defined LiPON glass-transition temperature of 207 & DEG;C. Combining interfacial stress and a gold seeding layer, our free-standing LiPON shows a uniformly dense deposition of lithium metal without the aid of external pressure. This free-standing LiPON film offers opportunities to study fundamental properties of LiPON for interface engineering for solid-state batteries. A free-standing thin-film solid electrolyte (LiPON) shows remarkable mechanical flexibility and the ability to form uniform and dense lithium metal deposition for future solid-state batteries.

Automated summary

We report a method to synthesize free-standing lithium phosphorus oxynitride (LiPON) with remarkable flexibility and Young's modulus of ~33 GPa. Our study reveals the chemistry of the Li/LiPON interface and a well-defined glass-transition temperature of LiPON at 207 °C. The free-standing LiPON film enables the study of fundamental properties for interface engineering in solid-state batteries.