PTVE was synthesized as a new active material for organic radical batteries. Cationic polymerization of a monomer bearing a TEMPO radical moiety took place. The spin concentration of PTVE was estimated to be 2.75 X 10(21) spins g(-1) (100% spin per repeating unit). The PTVE is extremely stable; there is no decrease in spin concentration when storing PTVE samples for more than a year under aerobic conditions at room temperature. The redox potential of PTVE is 3.55 V(vs. Li/Li+). A coin-type cell using a PTVE/VGCE composite electrode was also fabricated, and then performed charge/discharge measurements. The discharge capacity if PTVE is 114 mAh center dot g(-1) (84% of the theoretical value).