This communication reports a novel hyperbranched polymer with poly(ethylene glycol)9 segments and carboxylate groups. The combined advantages of single-ion conduction and a hyperbranched structure make the as-prepared polymers very promising as a solid-state polymer electrolyte for lithium ion batteries, by showing high ionic conductivity up to 1.2 × 10-4 S cm-1 at 85 °C, a high lithium transference number (tLi+) of 0.86, and simultaneously, a stable potential window up to 4.8 V versus Li+/Li.