The conjugated carbonyl compounds have emerged as an interesting opt ion as organic electrode materials for rechargeable batteries due to their unique advantages including high theoretical capacity and multi-electron reactions. A conjugated carbonylbased polyimide (PI) is synthesized through the imidization reaction of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and urea. Fourier transform infrared spectroscope （FT-IR）, X-ray diffraction（XRD），and scanning electron microscope （SEM） are performed to characterize their morphologies and structures. The electrochemical performance of PI is studied in two different electrolytes, NaClO4/EC∶DMC and NaClO4/EC∶PC, respectively. As a cathode material for sodium-ion batteries, PI exhibits a better specific capacity and cyclic stability in NaClO4/EC∶PC. At a current density of 0.3 C（1 C=118 mA·g-1）, the stable discharge capacity of 124 mAh·g-1 after 100 charging/discharging cycles can be achieved. The improved electrochemical performance of the PI electrode is attributed to the high ionic conductivity of NaClO4/EC∶PC, thus PI has the better dynamic performance in NaClO4/EC∶PC.