Novel thioether compound poly(ethene-1,1,2,2-tetrathiol) was synthesized, characterized and tested as cathode active material. The polymer was synthesized by facile one-step procedure and its chemical structure was confirmed by FT-IR, FT-Raman, element analysis, and XPS spectral analysis. The polymer had good electrochemical activity as cathode material for rechargeable lithium battery. It showed stable discharge specific capacity about 300mAhg−1 and discharge voltage above 2V. The thioether bond was deduced as the functional group. It was proposed that thioether bonds were oxidized to form thioether cations with the help of ether solvent, which offered energy storage.