Abstract: The low ion conductivity of the PEO-based electrolyte is mainly due to the higher crystallinity. Here, through blending and crosslinking, the oxide Al₂O₃ is used to disrupt the regular arrangement of the PEO crystal phase, and the small molecule polymer PEG is used to obtain more free chain segments, while enhancing the plasticity of the PEO main chain. The test results at 50 ℃ show that the ionic conductivity of PEO-PEG-Al₂O₃ is 2.19×10^-4S/cm, which can be stably electroplated and peeled for about 200 h at 0.1 mA/cm². The assembled LFP battery has an impressive specific capacity (~131 mAh/g) at 0.1 C and a stable coulombic efficiency. In addition, it is found through SEM that the improved PEO-PEG-Al₂O₃ electrolyte has fewer surface defects and can appropriately slow down the growth rate of lithium dendrites during cycling.