Mechanism Study of Li/Se Rechargeable Batteries in Different Electrolytes

Wednesday, May 14, 2014
Grand Foyer, Lobby Level (Hilton Orlando Bonnet Creek)
Y. Cui, A. Abouimrane (Chemical Sciences and Engineering Division, Argonne National Laboratory), and K. Amine (Argonne National Laboratory, King Abdulaziz University)
Lithium-seleniume battery has been reported as one of the promising new high energy density energy storage systems considering its high theoretical gravimetric capacity of 678 mAh/g and volumetric capacity density of 3268 mAh/cm3, which is comparable to that of S (3467 mAh/cm3). It has been reported that Se cathode could be cycled versus both Li and Na at room temperature. Moreover, a long cycle life up to 1000 cycles with high efficiency have been reported by Wang et al recently. We have proved that Se is reduced into Li2Se through the formation of intermediate polyselenide in the ether-based electrolyte by in-situ synchrotron techniques. However, a different mechanism is expected in the carbonate-based electrolyte based on the different voltage profiles. Then we experimentally demonstrated that the Se is directly transformed into Li2Se without any intermediate phase formation. These results further proved that the electrolytes have a significant effect on this battery system. This mechanism study provides essential information on strategy selection for furhter performance improvement of Li-Se baterry.