SBIR Phase I: Novel cathode for long-cycling capacitive deionization

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is in improving the energy efficiency and environmental sustainability of drinking water treatment. This project develops a new low-cost and environmentally friendly water treatment technology, called inverse Capacitive Deionization (i-CDI), that uses small amounts of electricity to soften or desalinate drinking water and industrial process water. i-CDI is more environmentally friendly than salt-based water softening, which adds salt to drinking water, and potentially much less expensive than reverse osmosis systems (RO) to install and maintain. New low-cost water treatment technologies are of increasing importance to densely populated communities at risk from drought or dwindling groundwater supply the Southwest United States, as well as large areas of Africa, Asia, and the Middle East. A similar water treatment technology using electricity to soften and desalinate drinking water, called Capacitive deionization (CDI), suffers from oxidation and fouling which deactivates the carbon electrode surface, severely limiting the operational lifetime. This deactivation can take place over the course of 24-72 hours. Therefore, while CDI may have energy benefits over RO, deactivation prevents CDI from being practically useful in the commercial or industrial water treatment market. The intellectual merit of this project is based on materials innovations that directly address the deactivation mechanism that previously made CDI systems impractical for commercial use, and without adding costly secondary components. In this i-CDI development project, the carbon electrodes used to separate salt from water will be treated to increase efficiency and lifetime of i-CDI. With this new i-CDI electrode technology, the benefits of CDI: high efficiency, low system cost, and less maintenance, can be achieved while maintaining long operational life. As the importance between energy and water continues to increase and fresh water supplies become further strained, the development of more efficient desalination technology will be crucial. This i-CDI process, with its stable salt separation capability, will see implementation in a variety of desalination applications including home, municipal, and industrial water softening and wastewater treatment.