Polymer-Assisted Solution Method to Metal Oxide Network Structures for Lithium-Ion Battery Electrodes

Rechargeable lithium-ion batteries have been extensively investigated for their promising application in hybrid electric vehicles because of their high energy and power densities and long cycle lifetime. A great effort has been made to synthesize a variety of electrode materials to improve the energy density, rate capability, and cycling stability. Nanostructured materials have received much attention as electrodes due to the short transport lengths for both electrons and lithium ions, higher electrode-electrode contact area, and better accommodation of the strain of lithium insertion/extraction.

Here we report a facile polymer-assisted chemical solution method to grow cobalt oxide, nickel oxide, bismuth oxide, and vanadium oxide network structures for lithium-ion battery anodes and cathodes. The carbon left from the decomposition of polymers is an effective binder between metal oxides and the nickel foam. As compared to the metal oxide powders prepared in a conventional way by using polymer binder and carbon black, these one-step direct growth electrodes showed much better lithium storage properties with high capacities, stable cyclability, and rate capability. For example cobalt oxides on nickel foam gave a capacity of 900 mAh/g at a current density of 1 A/g and 600 mAh/g at 4 A/g. The good performances of these electrodes could be attributed to intimate contact between the active material and the nickel foam, the porosity of the current collector, and the network structure of the active materials.