Improved Electrodes for Capacitive Deionization

This Small Business Innovation Research (SBIR) Phase I Project will develop improved monolithic carbon electrodes for capacitive deionization. Capacitive deionization is a new technology being developed for the purification of ocean and brackish well water. A constant voltage is applied and soluble salts are collected on the surface of porous carbon electrodes, thus purifying the water for human consumption or industrial processes. Unfortunately, the current carbon aerogel electrodes are very expensive and their ion storage capacity is relatively low. The problem is that the carbon aerogel electrodes only have small pores, which prevents complete and rapid ion transport through the material. A route to monolithic carbon electrodes with a combination of large (mesopores) and small pores (micropores) that is much easier and less expensive than the carbon aerogel electrode production process has been developed. The benefit of the mesopores is that they allow the liquid to penetrate the carbon for easy access to the high surface area micropores. This greatly increases the rate of salt uptake and the useful capacity of the electrodes. In Phase I TDA will develop monolithic porous carbon electrodes with the correct pore size distribution for use in capacitive deionization. In Phase II the production will be scaled up and the carbon electrodes will be tested in commercial capacitive deionization systems. Commercial Applications: Inexpensive mesoporous carbon electrodes could be used in capacitive deionization to purify water for human consumption and for industrial processes such as boiler feed. These carbon electrodes may also be useful in electrical energy storage, such as in capacitive energy storage