Al,2,O,3,/SiO,2, /PAN composite membrane was prepared as the separator for Li-ion batteries in order to replace the traditional microporous polyolefin membrane. PAN was polymerized by irradiation of ,60,Co γ-ray. The composite membrane has high porosity, and can be well wetted by liquid electrolyte. The amphoteric character of Al,2,O,3,/SiO,2, can scavenge acidic hydrogen fluoride, which is inevitably present in the LiPF,6,-based electrolytes used currently in the Li-ion batteries. With the composite membrane as a separator, the graphite/cathode cell exhibited good capacity retention. It is also found that the Li-ion cell fabricated in this manner not only has stable capacity retention, high temperature safety, but also shows good high-rate performance and overcharge proof performance.