In recent years, our group has focused on advancing metal oxide-based anode materials toward automotive targets. To reach these targets, it is important to investigate and understand the key parameters that increase reaction reversibility and rate performance. In this poster, we will show how the active material electronic conductivity plays a critical key role in both cycling performance and stability of metal oxide anodes. The electronic conductivity was controlled by adding advanced carbons (i.e. reduced graphene oxide and carbon nanotubes) to increase the inter-particle conductivity, while the intrinsic conductivity of the active material was manipulated by doping. Both of these strategies will be discussed.
More quantitatively, the electronic conductivity was probed by the Van Der Pauw Method and tied directly to the cycle life of lithium cells collected by chronopotentiometric charge/discharge curves. The nanostructural changes of the active materials were investigated by high resolution transmission electron microscopy (TEM), including identical location TEM. Finally, applying the lessons learned from these experiments, highly stable full cells with a metal oxide anode and lithium cobalt oxide cathode were achieved.