Magnetically Modified Asymmetric Supercapacitors

This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle life. Supercapacitors that utilize an aqueous electrolyte are limited to a maximum voltage of 1 volt due to the decomposition of water. Methods used to increase voltage include use of an organic electrolyte, which introduces additional complexity, cost and undesirable environmental concerns, or to use an asymmetric or hybrid configuration, with two different electrode materials. Supercapacitors that utilize MnO2 and carbon as the electrodes have been developed. However, due to changes in the MnO2 while cycling the capacitor to 2 volts, the MnO2 will change over time and lose its ability to cycle. One method around this problem, reported in the literature, is to charge the capacitor to 1.5 volts, resulting in reduced power and energy storage. In this Phase I program Giner, Inc. will demonstrate a novel solution to this problem by modifying the MnO2 positive electrode through the use of magnetic microparticles dispersed throughout the electrode structure. Using a Giner, Inc. novel high-energy density carbon as the negative electrode, complete, button-cell capacitors will be assembled and tested.