Chemically anchored liquid-PEO based block copolymer electrolytes for solid-state lithium-ion batteries

Abstract

Solid-state electrolytes are being considered the keystone element for the development of safer all-solid-state lithium-ion batteries. While poly(ethylene oxide) (PEO) solid-state polymer electrolytes are known to support a Li⁺ flux, satisfying conductivities are reached only above the melting point of the PEO crystallites (>65 °C) rendering PEO unpractical. Herein, by means of block-copolymer engineering, we design a mechanically clamped liquid-PEO electrolyte that combines the high ionic conductivity of a low molecular mass PEO while retaining the dimensional integrity of a solid material. Attractive ionic conductivities of about 0.01 mS cm⁻¹ are attained at room temperature without compromising mechanical properties. The electrolyte shows a wide electrochemical stability window and help in building a stable interface with lithium metal. Competitive performances are attained when integrating the developed materials into operational/functional prototype batteries highlighting the provided potential.