In this study, a series of nanocomposite polymer electrolytes (CPEs), PAN/LiClO4/SAP, with high conductivity are prepared based on polyacrylonitrile (PAN), LiClO4 and low content of the silica aerogel powder (SAP) prepared by the sol–gel method with ionic liquid (IL) as the template. The effect of addition of SAP on the properties of the CPEs is investigated by FTIR, AC impedance, linear sweep voltagrams and cyclic voltammetry measurements as well as the charge–discharge performance. It is found that the ionic conductivity of the CPE is significantly improved by addition of SAP. The maximum ambient ionic conductivity of CPEs is about 12.5 times higher than that without addition of SAP. The results of the voltammetry measurements of CPE-3, which contained 3wt% of SAP, show that the anodic and cathodic peaks are well maintained after 100 cycles, showing excellent electrochemical stability and cyclability over the potential range between 0V and 4V vs. Li/Li+. Besides, the room temperature discharge capacity measured at 0.5C for the coin cell based on CPE-3 is 120mAhg−1 and the capacity is retained after 20 cycles discharge, indicating the potential for practical use. This is perhaps the first report of the room temperature charge–discharge performance on the solid composite polymer electrolyte to the best of our knowledge.