AVS 57th International Symposium & Exhibition
    Energy Frontiers Topical Conference Tuesday Sessions
       Session EN+EM-TuA

Invited Paper EN+EM-TuA1
High-capacity and High-rate Metal Oxide Anodes for Li-ion Batteries

Tuesday, October 19, 2010, 2:00 pm, Room Mesilla

Session: Electronic Materials for Energy Conversion & Storage
Presenter: A.C. Dillon, National Renewable Energy Laboratory
Authors: A.C. Dillon, National Renewable Energy Laboratory
C. Ban, National Renewable Energy Laboratory
L.A. Riley, University of Colorado
A.S. Cavanagh, University of Colorado
S.M. George, University of Colorado
Y.S. Jung, National Renewable Energy Laboratory
Z. Wu, National Renewable Energy Laboratory
Y. Yan, National Renewable Energy Laboratory
S.-H. Lee, University of Colorado
Correspondent: Click to Email
Significant advances in both energy density and rate capability for Li-ion batteries will be necessary for implementation in next generation electric vehicles. By employing metal oxide nanostructures, it is possible to achieve Li-ion anodes that have significantly higher capacity than the state-of-the-art graphite technology. For example we have demonstrated that thin film MoO3 nanoparticle electrodes (~2 µm thick) have a stable reversible capacity of ~630 mAh/g when tested at C/2.1 By fabricating more conventional electrodes (~35 µm) with a conductive additive and binder, an improved reversible capacity of ~1000 mAh/g is achieved.2 The increased capacity for the MoO3 coin cell electrode compared to the thin film electrode may be attributed to improved electronic/ionic mobility with the conductive additive and more complete access to the nanostructures. We have also demonstrated that by applying a thin atomic layer deposition coating of Al2O3, improved rate capability for the high volume expansion MoO3 is achieved for thick more conventional electrodes3.

More recently we have focused our work on iron oxide nanostructures, as iron is an inexpensive, abundant and a non-toxic material. Furthermore, we have synthesized binder-free, high-rate capability electrodes. The electrodes contain Fe3O4 nanorods as the active lithium storage material and carbon single-wall nanotubes (SWNTs) as the conductive additive. The highest reversible capacity is obtained using 5 wt.% SWNTs, reaching 1000 mAh/g (~2000 mAh/cm3) at C rate when coupled with a lithium metal electrode, and this high capacity is sustained over 100 cycles. Furthermore, the electrodes exhibit high-rate capability and stable capacities of 800 mAh/g at 5C and ~600 mAh/g at 10C. Scanning electron microscopy indicates that this high-rate capability is achieved because Fe3O4 nanorods are uniformly suspended in a conductive matrix of SWNTs. Raman spectroscopy is employed to understand how the SWNTs function as a highly flexible conductive additive. We expect that this method can be used to achieve other binder-free anodes as well as cathodes with similar high-rate capability4.

(1) Lee, S.-H.; Kim, Y.-H.; Deshpande, R.; Parilla, P. A.; Whitney, E.; Gillaspie, D. T.; Jones, K. M.; Mahan, A. H.; Zhang, S. B.; Dillon, A. C. Adv. Mat. 2008, 20, 3627-3632.

(2) Riley, L. A.; Lee, S.-H.; Gedvilias, L.; Dillon, A. C. Journal of Power Sources 2010, 195, 588-592.

(3) Riley, L. A.; Cavanagh, A. S.; George, S. M.; Jung, Y.-S.; Yan, Y.; Lee, S.-H.; Dillon, A. C. ChemPhysChem 2010, in press.

(4) Ban, C.; Wu, Z.; Gillaspie, D. T.; Chen, L.; Yan, Y.; Blackburn, J. L.; Dillon, A. C. Advanced Materials 2010, in press.