Nano-Engineered Anodes for Lithium-ion Batteries

Lithium-ion technology has revolutionized the portable electronics industry by providing high energy density batteries at affordable prices. The popularity of lithium-ion batteries is now steadily spreading into other industries, such as hybrid electric vehicles (HEVs) where the application requirements differ from those for portable electronics. For example, the energy storage materials (such as lithium cobalt oxide used in cathodes and graphiticcarbon used in anodes) optimized for the portable electronics industry are not suitable for HEVs. While these materials offer high energy densities (light weight and small size), they are limited in other key performance areas ¿ e.g., power (rate) capability, cycle life, calendar life, and thermal stability. Therefore, a new family of materials optimized for the HEV applications are required to fill these critical performance deficiencies. This project addresses the need for novel HEV battery anodes that will have high power capability, long cycle life, long calendar life, and good thermal stability. The approach involves the development of a family of nano-engineered anode materials based on lithium titanium oxide (Li4Ti5O12 or LTO). These nano¬materials typically have average particle sizes less than 100nm. The high power capability will be made possible by the high surface area that is a characteristic of the nano-particles. The electronic conductivity and rate capability of the anode will be enhanced by incorporating dopants into the LTO. LTO also will provide high thermal stability, primarily because it operates at higher voltages compared to graphite. Commercial Applications and other Benefits as described by the awardee: Large-format lithium-ion batteries could power the next-generation of HEVs and Plug-in Hybrid Electric Vehicles (PHEVs). A nano-LTO based battery system also would have several attributes that are desirable to other applications, such as power tools, back-up power systems, and energy storage for photovoltaic power systems.