Mayandi Ramanathan

Lithium-Ion Cell Components and Their Effect on High-Power Battery Safety

Li-ion batteries with high power and high energy are used for new applications such as electric vehicles, for which safety concern is essential. We review the state of the art in the research to optimize the safety of all the elements of the batteries already available on the market. We also report on the recent batteries that are not yet commercialized, but have been tested as demonstrators, which pass all the security tests without the help of any battery monitoring system with almost unlimited cycling life, which is expected to reduce significantly the cost of the electric vehicles.

Microstructure-ORR Activity Relationships in Pd3M (M = Cu, Ni, Fe) Electrocatalysts Synthesized at Various Temperatures

The oxygen binding energy (BEO), considered to be an important descriptor for ORR catalytic activity on transition metal alloys, was calculated using ab initio Density Functional theory calculations to probe the ORR activity of Pd3M/C (M = Fe,Ni,Cu) alloys. Variation in BEO with binding site were ascribed to changes in ORR activity due to varying catalytic surfaces developed at different annealing temperatures. Relative binding energies of *O and *OH predicted higher ORR activity for Pd3Cu on bulk surfaces and for Pd3Fe on Pd skin surfaces when compared to pure Pd. Pd3M/C (M = Fe,Ni,Cu) electrocatalysts were synthesized at temperatures from 300 to 800{degree sign}C and the electrochemical surfaces were characterized by Cyclic Voltammetry. Typical rotating disk currents for Pd3M alloys showed higher ORR activity for Pd3Fe/C and Pd3Cu/C annealed at higher temperatures. Koutechy-Levich Plots for Pd3Fe/C and Pd3Cu/C showed four electron transfer for oxygen reduction and better kinetic parameters than Pd.