An organic radical battery (ORB) is a type of battery first developed in 2005.[1] As of 2011, this type of battery was generally not available for the consumer, although their development at that time was considered to be approaching practical use.[2] ORBs are potentially more environmentally friendly than conventional metal-based batteries, because they use organic radical polymers (flexible plastics) to provide electrical power instead of metals. ORBs are considered to be a high-power alternative to the Li-ion battery. Functional prototypes of the battery have been researched and developed by different research groups and corporations including the Japanese corporation NEC.[1]
The organic radical polymers used in ORBs are examples of stable radicals, which are stabilized by steric and/or resonance effects.[2] For example, the nitroxide radical in (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), the most common subunit used in ORBs, is a stable oxygen-centered molecular radical. Here, the radical is stabilized by delocalization of electrons from the nitrogen onto the oxygen. TEMPO radicals can be attached to polymer backbones to form poly(2,2,6,6-tetramethyl- piperidenyloxyl-4-yl methacrylate) (PTMA). PTMA-based ORBs have a charge-density slightly higher than that of conventional Li-ion batteries, which should theoretically make it possible for an ORB to provide more charge than a Li-ion battery of similar size and weight.[2]
As of 2007, ORB research was being directed mostly towards Hybrid ORB/Li-ion batteries because organic radical polymers with appropriate electrical properties for the anode are difficult to synthesize.[3]