Event
MSE Seminar-Prof. Chunsheng Wang, University of Maryland
Friday, March 27, 2009
1:00 p.m.
Room 2108, Chemical and Nuclear Engineering Bldg.
Annette Mateus
301 405 5207
amateus@umd.edu
"Advanced Electrode Materials for Li-ion Batteries"
Lithium ion batteries are currently being used to power an increasingly diverse range of applications, and have been recognized as a critical enabling technology to make the Electric Vehicle/Hybrid Electric Vehicle (EV/HEV) a success. One challenge to the traditional Li-ion batteries for EV applications is their low energy density and poor power density. High energy Si anode (capacity is 10 times higher than currently used carbon anode) and high power LiFePO4 cathode (electrode can be charged/discharged in a few seconds) are promising electrode materials for EV/HEV batteries. However, the mechanism for high power of LiFePO4 is still not fully understood, and the poor cycling stability of Si limits its practical application. Our research demonstrated that the high power of LiFePO4 is induced by both fast phase transformation and rapid Li ion diffusion in LiFePO4. The diffusion coefficient and interface mobility are calculated by us using a mixed control phase transformation model. Si anodes with porous structure can largely improve charge/discharge cycling stability.
