If it were not for energy storage devices like batteries and capacitors, much of the technology we use every day would not exist or have a very different form. Unfortunately, these two technology are almost polar opposites with their characteristics and the ideal energy storage system would be somewhere in the middle. Now researchers at Michigan Technological University have created a new material which does exist in that middle and could impact many other technologies.
Batteries store energy by moving ions around inside it while capacitors store energy by separating opposite charges. The different mechanics involved allow batteries to store large amounts of energy, but their charge and discharge rates can be quite slow as the ions have to move through the cell, while capacitors can only store so much energy, but the charges they hold can move very quickly. Manganese dioxide (MnO2) however can be made into a chemical capacitor, which is a cross between batteries and physical capacitors, with superb properties, but has proven difficult to produce in the correct structure until now. The researchers were able to produce forests of MnO2 nanorods using electrophoretic deposition, which uses an electric field to align particles as they collect on a substrate.
When tested the MnO2 chemical capacitor was able to store 90% its original charge after 2000 charge/discharge cycles, and also stored more energy and delivered it faster than comparable carbon-based physical capacitors. The researchers envision this being used in electric vehicles or possibly coupled to solar cells.