Long-Life Lithium-Metal All-Solid-State Batteries and Stable Li Plating Enabled by InSitu Formation of Li3 PS4 in the SEI Layer.

Abstract

An ultrastable and kinetically favorable interface is constructed between sulfide-poly(ethylene oxide) (PEO) composite solid electrolytes (CSEs) and lithium metal, via insitu formation of a solid electrolyte interphase (SEI) layer containing Li3 PS4 . A speciallydesigned sulfide, lithium polysulfidophosphate (LPS), can distribute uniformly in the PEO matrix via a simple stirring process because of its complete solubility in acetonitrile solvent, which is advantageous for creating a homogeneous SEI layer. The CSE/Li interface with high Li+ transportation capability is stabilized quickly through insitu formation of a Li3 PS4 /Li2 S/LiF layer via the reaction between LPS and lithium metal to inhibit lithium dendrite growth. A Li/Li symmetric cell with the LPS-integrated CSE exhibits constant and small CSE/Li resistance of 10Ωcm2 during cycling, delivering stable cycling for 3475h at a current density of 0.2mAcm-2 and a high critical current density of 0.9mAcm-2 at 60°C. Impressive electrochemical performance is also demonstrated for LiFePO4 /CSE/Li all-solid-state batteries with capacity of 127.6mAhg-1 after 1000cycles at 1C.