The news is reported in the latest edition of the Royal Society of Chemistry journal Chemical Communications.

With recent advances in the technology of portable electronic devices, there is a demand for flexible batteries to power them.

Drs Hiroyuki Nishide, Hiroaki Konishi and Takeo Suga at Waseda University have designed the battery - which consists of a redox-active organic polymer film around 200 nanometres thick. Nitroxide radical groups are attached, which act as charge carriers.

The battery has a high charge/discharge capacity because of its high radical density.

Dr Nishide said: "This is just one of many advantages the `organic radical` battery has over other organic based materials which are limited by the amount of doping.

"The power rate performance is strikingly high - it only takes one minute to fully charge the battery. And it has a long cycle life, often exceeding 1,000 cycles."

The team made the thin polymer film by a solution-processable method - a soluble polymer with the radical groups attached is "spin-coated" onto a surface. After UV irradiation, the polymer then becomes crosslinked with the help of a bisazide crosslinking agent.

A paper-like polymer based rechargeable battery

A drawback of some organic radical polymers is the fact they are soluble in the electrolyte solution which results in self-discharging of the battery - but the polymer must be soluble so it can be spin-coated.

However, the photocrosslinking method used by the Japanese team overcomes the problem and makes the polymer mechanically tough.

Dr Nishide said: "This has been a challenging step, since most crosslinking reactions are sensitive to the nitroxide radical."

Professor Peter Skabara, an expert in electroactive materials at the University of Strathclyde , praised the high stability and fabrication strategy of the polymer-based battery.

He said: "The plastic battery plays a part in ensuring that organic device technologies can function in thin film and flexible form as a complete package."

Dr Nishide envisages that the organic radical battery could be used in pocket-sized integrated circuit cards, used for memory storage and microprocessing, within the next three years.

He said: "In the future, these batteries may be used in applications that require high-power capability rather than high-energy density, such as a battery in electronic devices and motor drive assistance in electric vehicles."

With thanks to Alison Stoddart for the original article.

Royal Society of Chemistry.

Link to journal article:

Photocrosslinked nitroxide polymer cathode-active materials for application in an organic-based paper battery
Takeo Suga, Hiroaki Konishi and Hiroyuki Nishide, Chem. Commun., 2007
DOI: 10.1039/b618710b