SBIR Phase II: The Development of Higher Voltage, Longer Life and Lower Cost Activated Carbon Materials for Supercapacitors

Coulometrics, Chattanooga TN

Investigators

Abstract

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is in significantly increasing the ways supercapacitors and lithium ion batteries are used today. Supercapacitors offer very high power capabilities and high energy efficiency and have been used in many renewable energy applications such as hybrid buses and wind turbines. Currently, their use is limited due to high cost and low energy density relative to Li-ion batteries. Coulometrics has developed a proprietary process that can modify low cost activated carbon materials into supercapacitor grade carbons with 25% higher energy density and twice the current lifespan of existing materials. These critical developments will lower the overall system cost and improve cell life allowing for more widespread use of supercapacitors in renewable energy applications. Coulometrics has also shown that a very similar process can be used to convert natural graphite to lithium ion grade anode materials with higher energy density and significantly lower cost. This process will also enable a Northern American company to become the first producer of graphite for lithium ion batteries on the continent which can significantly reduce lithium ion battery cost for applications such as electric vehicles. Both projects will have additional environmental benefits including reduced greenhouse gas emissions, less burning of fossil fuels, and help protect the environment. The project seeks to break through a significant barrier that has kept ultracapacitor voltage and energy density stagnant for over a decade and significantly reduce costs of lithium ion battery carbon materials. Supercapacitor companies all produce products with different carbons, electrolytes, cell construction, etc. and yet are all confined to the same performance specifications. We believe that this is related to oxidation/reduction reactions that occur on the carbon surface; a fairly intuitive hypothesis; however attempts at solutions have been futile. The surface treatment we developed in Phase I has resulted in a reduction of these oxidation/reduction currents by more than 50%. This technology will lead to the largest performance gains in the ultracapacitor industry in over 10 years. Additionally, one of the most challenging factors limiting market growth for ultracapacitors is their high cost, of which activated carbon accounts for 27%. Coulometrics' treatment applied to inexpensive water filtration carbon, also developed in Phase I, has shown very similar performance enhancements, and will cost up to 95% less than commercial activated carbon materials. The surface modification process for graphitic carbons will enable the low cost and high quality production of carbon anode materials for lithium ion batteries based on natural graphite. This breakthrough can significantly reduce lithium ion battery cost which is a key element for more wide spread adoption of electric vehicles which will help reduce our nation's dependence on the need to import foreign oil.