NSF Award
8800822
The prime objective of the previous Phase I effort was to establish whether two new lithium salts, LiN (CF3SO2)2 and LiSbF6, in combination with a suitable solvent, could outperform state of the art electrolytes in Li/Ti S2 non-hermetic full cells. It was determined and demonstrated that LiN(CF3SO2)2 had the desirable characteristics for use in such lithium systems. The Phase II work will be in three areas: (1) utilizing established techniques of purification and synthesis to prepare LiN (CF3SO2)2 and two other, new organic onion lithium salts, (2) determination of the reactions of these salts in both lithium and solvent at extreme potentials and under full cell cycling conditions, and (3) doing full cell cycling studies in Li/TiS2 test cells cycled at current densities relevant to commercial applications. Rechargeable lithium power sources which provide high energy densities at high rates have many potential commercial uses as power systems in satellites, in portable communications equipment and for other load-leveling applications. A key problem in the past was the poor cycleability of the lithium electrode. Commonly used salts are deficient with respect to rechargeables owing either to intrinsic instability or lack of proper purification. The PI will therefore synthesize, purify and test in a full cell, three salts that are not commercially available and hopes to ultimately commercialize a very safe rechargeable lithium battery.
