One‐Step Polymerizations Enable Facile Construction and Structural Optimization of Graft Copolymer Electrolytes

Abstract The development of poly(ethylene oxide) (PEO)‐based solid polymer electrolytes (SPEs) is limited by the semi‐crystalline nature of PEO and the extremely strong EO‐Li + interactions. To promote the rapid migration of Li + , a one‐step method combining radical polymerization and ring‐opening polymerization catalyzed simultaneously by lithium carboxylate is proposed to construct multi‐component graft copolymer electrolytes (GCPEs) in this study. Tailored macroinitiator with catalytic and initiated sites (PAALi(OH‐Br)) realizes one‐step polymerizations of vinyl monomers and cyclic monomers, and provides GCPEs with poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL) side chains. The grafted structure of GCPE greatly facilitates the intra‐chain hopping of Li + , resulting in excellent ionic conductivity. The introduction of PCL further improves the t Li+ of GCPE. The three‐component graft copolymer electrolyte constructed by polystyrene (PS), PEO, and PCL exhibits high tensile stress (1.62 MPa), a high ionic conductivity (2.4 × 10 −5 S cm −1 , 30 °C), and a high t Li+ of 0.47 and high electrochemical stability.