Molecular Brush with Dense PEG Side Chains: Design of a Well-Defined Polymer Electrolyte for Lithium-Ion Batteries

TLDR

PEO side chains act as efficient conductors for lithium salt. The authors synthesized bottlebrush polymers with densely grafted short PEO side chains and backbone‑bound lithium cations via controlled radical polymerization, enhancing Li‑ion transport and transference number. The resulting solid polymer electrolyte shows 4.49 × 10⁻⁵ S cm⁻¹ conductivity at 30 °C and delivers high capacity with excellent cycling, indicating its suitability for lithium‑ion batteries.

Abstract

Herein, we designed a series of well-defined bottlebrush-like macromolecules with short and densely grafted poly(ethylene oxide) (PEO) side chains through several controlled radical polymerization methods to prepare solid polymer electrolytes (SPEs). The PEO side chains can work as sensational conductors for lithium salt. Moreover, these macromolecules own lithium cations linked on the backbone, which can facilitate the transport of Li ions and thus improve the lithium-ion transference number. The prepared SPE exhibits a considerable ion conductivity of 4.49 × 10–5 S cm–1 at 30 °C owing to its specific structure. Furthermore, the high capacity and excellent cycle performance demonstrate the foreseeable application of the obtained electrolyte in the lithium-ion battery.