Dr. Ming Au of the Savannah River National Laboratory, will be presenting her talk entitled, "Nanostructured Metals and Metal Oxides for Anodes of Li-Ion Batteries" this week.

Currently, carbon base anodes are being used for Li-ion rechargeable batteries through Li ion intercalation process. The theoretic capacity is limited at 372 mAh/g. The volume expansion and breakdown of solid electrochemical interface (SEI) of carbon anodes during overcharging is one of the reasons of thermal runaway and fire ignition. Searching for new anode materials that possesses higher energy storage capacity and inherent fire safety is not only scientist’s passion, but the mandate of industries and customers, particularly for plug-in hybrid vehicles and portable power sources.

It is found that metal oxides and metals can host Li ions through conversion process that changes lattice structure of metal oxides or forms metal alloys. The theoretic capacity of metal oxides and metals is in the range of 500 ~ 4000 mAh/g. The metal oxides do not react with polymer electrolyte and generate exceed heat. The aligned nanostructure, such as nanorods, creates large inter-rods space that is capable to store the charges and accommodates the volume expansion caused by conversion. It is expected the aligned nanorods of metal oxides will offer high energy density and power density and inherent safety. Growing free standing nanostructured anode materials on current collectors directly without additives and binders represent a new trend of anode fabrication with simplified process and low cost. In other hand, the nanoparticles of metal oxides can be assembled as the hollow spheres that offers unique feature for anodes of Li-ion rechargeable batteries. We will present our experimental results and discuss the aspects related to practical applications in the conference.