Electrochemical properties and chemical structures of metal-doped SiO anodes for Li-ion rechargeable batteries

We have used a codeposition technique to develop high-capacity metal-doped SiO anodes for use in Li-ion rechargeable batteries, and we have measured their electrochemical properties. Cycle maintenance rates were roughly 82% after 400 cycles with a manganese oxide cathode. Initial charge-discharge coulombic efficiencies were roughly 84% without Li addition and nearly 100% with Li addition to the anodes for their full performance using Li half-cells. The discharge capacities per unit weight of these anodes were about 3-4 times that of graphite. X-ray photoelectron spectroscopy analysis shows that the anodes have a different chemical structure from that of nondoped SiO anodes [J. Electrochem. Soc., 152, A2089 (2005)], that metal compounds are not formed in the doped metals, and that the valence of Si changed from 0 to 4+, and back to 0, during initial charge and discharge. Doped-metal works as an electron transporter, helping diffusion of Li ions in the electrode, and improves the electrical properties of the material.