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Exploring Nanowire Arrays and Graphene Hybrid Materials for Lithium Ion Battery

Exploring Nanowire Arrays and Graphene Hybrid Materials for Lithium Ion Battery. Yiying Wu Chemistry Department Ohio State University. How does the Li-ion battery work?. Linden, D. Handbook of batteries 2002. Anode: an overview. Cathode materials: an overview.

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Exploring Nanowire Arrays and Graphene Hybrid Materials for Lithium Ion Battery

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  1. Exploring Nanowire Arrays and Graphene Hybrid Materials for Lithium Ion Battery Yiying Wu Chemistry Department Ohio State University

  2. How does the Li-ion battery work? Linden, D. Handbook of batteries2002

  3. Anode: an overview

  4. Cathode materials: an overview

  5. Part 1: Co3O4 nanowire arrays for Li-ion anode Transition metal oxides such as CoO, Co3O4, NiO, FeO, Fe3O4 Mechanism: CoO + 2Li+ +2e- Li2O + Co - Poizot, P. et al, Nature407, 496 (2000). - M. Armond & J.-M. Tarascon, Nature 451, 652 (2008).

  6. Advantages of NW arrays for battery electrode: • Small size --- short Li+ ion diffusion length in electrode materials; • High surface area --- low current density; • Accommodation of strain --- long cycle life; • Easy mass transport for electrolyte solution; • Direct contact with current collecting substrate. • No inactive materials. • Advantages for other applications: • Decouple the direction of light absorption from charge separation; • Antireflection for efficient light absorption;

  7. NH3 Co3O4 nanowire arrays: an ammonia-evaporation-induced method Co2+ + 6 NH3 Co(NH3)62+ Co(NH3)62+ + 2 OH-  Co(OH)2 + 6 NH3 6 Co(OH)2 + O2  2 Co3O4 + 6 H2O • Advantages: • mild, facile, and large-area growth; • direct growth on conducting substrate; --- Y. Li, B. Tan, & Y. Wu, J. Am. Chem. Soc,128, 14258 (2006). --- Y. Li, B. Tan, Y. Wu. Chem. Mater.20: 567-576 (2008). --- Y. Li, B. Tan, Y. Wu. , Nano Letters,8: 265-270(2008) . Yanguang Li

  8. Co3O4 nanowire arrays --- Y. Li, B. Tan, & Y. Wu, J. Am. Chem. Soc,128, 14258 (2006).

  9. NW internal structure: single-crystalline and mesoporous 5 nm 500nm 180 nm 20 nm

  10. Patterning the Nanowire Growth

  11. Discharging-charging curves for Co3O4 NWs CoO Co3O4 Li metal Ti foil Co3O4 Co+Li2O Li+ electrolyte Half-cell testing Constant current at 1C (1 Li+ per Co3O4 formula unit in 1hr) --- Y. Li, B. Tan, Y. Wu. , Nano Letters,8: 265-270(2008) .

  12. Capacity at 1C Nanowire array Broken Nanowire Graphite Commercial powder NW arrays: 700 mAh/g retention capacity after 20 cycles

  13. Rate Capability NW arrays Powder electrode

  14. Summary • A facile method has been developed for synthesizing Co3O4 nanowire arrays; • These Co3O4 nanowire arrays have been shown to possess large capacity and rate capability; • Graphene-based composites have been developed to reduce carbon loading and thus increase the overall energy density of the electrode. Yanguang Li

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