Preparation and electrochemical characterization of overlithiated spinel LiMn{sub 2}O{sub 4}
- EIC Labs., Inc., Norwood, MA (United States)
Parasitic reactions taking place at the carbon anode are primarily responsible for the capacity loss that occurs during the formation cycles of a carbon/LiMn{sub 2}O{sub 4} Li-ion battery. The additional amount of cathode material required to supplement this irreversible capacity leads to a reduction in the specific energy of the battery. This can be overcome with the use of the overlithiated cathode material, Li{sub 1{minus}x}Mn{sub 2}O{sub 4}, in which the excess Li, x, is used to compensate the irreversible capacity at the anode. This investigation highlights the usefulness of n-BuLi reduction to synthesize Li{sub 1+x}Mn{sub 2}O{sub 4} from LiMn{sub 2}O{sub 4} and demonstrates the long-term rechargeability of these materials in Li cells. Reaction of cubic spinel LiMn{sub 2}O{sub 4} with BuLi to form overlithiated cathode materials of the general formula Li{sub 1+x}Mn{sub 2}O{sub 4} (x = 0.1--1.0) was found to be quantitative under mild conditions at room temperature. The X-ray diffraction of each Li{sub 1+x}Mn{sub 2}O{sub 4} indicated that the chemically introduced Li(x in Li{sub 1+x}Mn{sub 2}O{sub 4}) could be extracted nearly 100% in a voltage plateau around 3.0 V vs. Li{sup +}/Li. Furthermore, the rate capability and cycle life of these materials when cycled between 4.25 and 3.0 V were identical to those of the baseline LiMn{sub 2}O{sub 4}. In balanced carbon/LiMn{sub 2}O{sub 4} full cells, the chemically inserted Li could be fully utilized to compensate for the irreversible capacity loss occurring in their formation cycles.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 624293
- Journal Information:
- Journal of the Electrochemical Society, Vol. 145, Issue 4; Other Information: PBD: Apr 1998
- Country of Publication:
- United States
- Language:
- English
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