Herein, solid polymer electrolytes (SPEs) were designed and fabricated via the photopolymerization of a macromolecular crosslinker with boronic ester bonds and poly(ethylene glycol) diacrylate (PEGDA) with different molecular weights under UV irradiation in the presence of a photoinitiator. The boronic ester-based crosslinker was synthesized via the dehydration reaction of ortho-aminomethyl-phenylboronic acid-terminated poly(propylene glycol)-b-poly(ethylene glycol)-b-poly(propylene glycol) and 2,3-dihydroxypropyl methacrylate. The covalently cross-linked polymer stabilized electrolytes (PSEs) containing boronic ester bonds possessed improved ionic conductivity, self-healing properties, and a wide electrochemical window (5.3 V vs. Li⁺/Li).