In laboratory experiments, the porphyrin molecule increases the charging speed of batteries when incorporated into electrodes.
KIT / HIU
Researchers at Karlsruhe Institute of Technology (KIT) have presented a high-performance storage material with which lithium-ion batteries can be charged particularly quickly. “The storage properties are exceptional because the material has the storage capacity of a battery, but works as fast as a super capacitor”, says Professor Maximilian Fichtner from the Helmholtz Institute Ulm, who leads the research together with Professor Mario Ruben from the KIT Institute of Nanotechnology.
In order to improve this property of the lithium-ion battery, functional groups were added to the organic molecule copper porphyrin. When the battery cell is first charged, this triggers structural and electrically conductive cross-linking of the material, which stabilises the electrode structure and ensures very rapid and reversible storage of lithium ions. Several thousand charging and discharging cycles could be performed in the laboratory.
Even faster charging possible
At an average of three volts, storage capacities of 130 to 170 milliampere hours per gram (mAh/g) were measured for this material. Charging and discharging took only one minute. The researchers assume that the storage capacity could be increased by another 100 mAh/g and this could also be operated with the more common element sodium.
The researchers intend to use storage materials based on natural raw materials. Many materials that improve lithium-ion battery properties in the laboratory are expensive, toxic or environmentally harmful.