We have developed the new energy storage system utilizing a radical redox reaction of poly (2,2,6,6-tetramethylpiperidinoxy methacrylate), PTMA. The coin-type cell with PTMA cathode demonstrates the charge capacity of is 72 Ah/kg, which corresponds to 65% of the theoretical capacity, and the coulombic efficiency was 90% in first charge-discharge cycle. The results indicate that the stable polyradical cathodes are promising materials due to their high charge utilization and the possibilities for the wide diversity of molecular design.

We have developed a high-power organic radical battery for information technology equipment such as personal computers (PCs). The battery provides several minutes of backup power without an external uninterrupted power source. Since the built-in battery makes energy conversion from AC to DC, or DC to AC, unnecessary, it protects equipment from power failure with no loss of energy. The fabricated battery shows a high power density of 1 kW/L and is capable of driving a desktop PC for several minutes. The use of purely organic polyradicals, poly (2,2,6,6-tetramethylpiperidinyloxy mathacrylate), for the cathode active material opens up a new field of high power density, environmentally friendly batteries.