Solid polymer electrolytes based on poly(1,4-butylene adipate) (PBA) and LiCIO4 were hybridized with Li+ conductive lithium aluminum germanium phosphate (Li1.5Al0.5Ge1.5(PO4)(3), LAGP) to obtain highly conductive and flexible solid electrolyte film. Ionic conductivity, mechanical property and electrochemical stability were enhanced by incorporating an appropriate amount of LAGP into the PBA-based solid polymer electrolyte, and the optimum content of LAGP in the hybrid solid electrolytes was approximately 60-80 wt%. The all-solid-state Li/LiNi0.6Co0.2Mn0.2O2 cell employing the optimized hybrid solid electrolyte exhibited an initial discharge capacity of 169.5 mAh g(-1) with good capacity retention at 55 degrees C.