High Power Density Li-Ion Batteries with Good Low Temperature Performance

Conventional and plug-in hybrid electric vehicles (HEVs) require economical and safe rechargeable Li-ion batteries that have high power, good cyclability, long calendar life, and good low temperature performance. Plug-in HEV batteries also need to have high energy density. Currently available Li-ion batteries significantly degrade at sub-zero temperatures and do not meet the requirements. This project will develop safe and high performance electrode materials to fulfill the requirement of the two HEV applications. Utilizing these electrode materials in conjunction with high performance liquid electrolytes will lead to Li-ion batteries with good low temperature performance. In addition, the lithium plating problem, which is commonly found in conventional Li-ion batteries, will be overcome. In Phase I, a nanocomposite cathode material was produced by a simple and economical synthesis process and was demonstrated to have good low temperature performance. In Li-ion cells (capacity: 9 ¿ 12 mAh), the nanocomposite cathodes exhibited excellent cycling stability. Additionally, important powder properties, which control the rate capability of the nanocomposite cathode, were discovered. In Phase II, the synthesis process for producing nanocomposite cathode materials will be optimized, and the electrode materials will be implemented in Li-ion batteries. Additionally, a cathode material, suitable for plug-in HEV Li-ion batteries, will be developed. High performance prototype Li-ion batteries, which will avoid the lithium plating problem at low temperatures and fast charge rates, will be fabricated and tested. Commercial Applications and Other Benefits as describde by the awardee: The technology should enable the development of low cost Li-ion batteries that would be safe for HEV applications. In addition, Li-ion batteries are ubiquitous in both consumer and industrial sectors. All of these applications have nearly identical needs ¿ more energy, higher safety, faster charges, and high power (in some cases).