High Energy Density Li-ion Polymer Batteries With Nanocomposite Cathodes

The energy density and the average operating voltage of Li-ion batteries can be enhanced by utilizing new cathode chemistries that have significantly higher capacity and higher open circuit voltage than those of start-of-the-art LiCoO2 cathode. The proposed program focuses on developing novel nanocomposites with a theoretical energy density of 800 Wh/kg, which is more than 60% higher than that of the practical energy density of LiCoO2. In Phase I, we developed a process of producing nanocomposite cathode powders. The crystallite size of particles was in the range of 50 ? 300 nm. It was demonstrated that cathodes made of the nanocomposite powder were electrochemically active and exhibited high first charge capacity, > 85% of the theoretical capacity. Working with rechargeable Li-ion battery manufacturers and leading researchers, we will demonstrate that it is possible to produce stable and high energy density nanocomposite cathodes by manipulating the structure and the composition. Additionally, we will fabricate prototype Li-ion polymer cells consisting of cathodes made of the nanocomposite powders. Processing methods will be developed for producing large cathode tapes with nanostructured powders. The powder synthesis process will be optimized for producing kilogram quantities. The overall goal of the Phase II program is to achieve Li-ion polymer cells with an energy density of 200 Wh/kg for a large number of discharge-charge cycles ( 1000) and an average voltage of > 4.4 V.