The researchers tested an electrode made from organic copper porphyrin, and measured storage capacities of 130-170 milliamperes per gram (mAh/g) at an average of 3 volts, with experiments suggesting that the capacity could be increased by as much as another 100 mAh/g.
The researchers also measured charging/discharging times of just one minute, considerably faster than current lithium-ion technology. “The storage properties are exceptional because the material has the storage capacity of a batter but works as fast as a supercapacitor,” explains lead researcher Maximilian Fichtner.
Porphyrins occur frequently in nature, forming the basis of chlorophyll in plants and blood in humans and animals. Variants of the material are already used industrially in paints and inks. For the electrode, the researchers added functional groups to the organic copper porphyrin molecule, with these, the structure becomes crosslinked and improves the electrode’s stability. According to a press release from Karlsruhe Institute of Technology, which sponsored the research, the structure allows for several thousand charge/discharge cycles.