Enhanced ionic conductivity and mechanical properties via dynamic-covalent boroxine bonds in solid polymer electrolytes

Abstract Herein, we designed the solid polymer electrolytes (SPEs) via the polymerization of poly(ethylene glycol) diacrylate (PEGDA) with different molecular weights under a UV irradiation in the presence of 2-formyl benzene boric acid (PBA)- terminated poly(propylene glycol)-b-poly(ethylene glycol)-b-poly(propylene glycol) (NH2-ED2000-NH2) (diPBA-ED2000). The SPEs with the boroxine structure were obtained by the dehydration and condensation of the diPBA-ED2000. The ionic conductivity and mechanical strength of SPEs with the formed boroxine structure can be effectively enhanced. Moreover, the SPEs with boroxine structure possessed good flexibility, self-supported, healable properties, wide electrochemical window (5.5 V vs. Li+/Li), and improved interfacial stability between the SPE and the Li electrode.