Rechargeable Lithium Cells with High Energy Density Transition Metal Compound Cathodes - Characterization in AA-Size Cells.
Final rept. 24 Sep 89-1 Mar 92,
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV SILVER SPRING MD
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Lithiumlithium cobalt oxide cells were packaged in Size AA containers. Cell capacity was 0.85 Ah for discharge of the LixCoO2 cathode over the range of x from zero to unity 100 percent depth of discharge DOD. Cells were discharged at 37.5, 50, and 75 percent DOD. The latter depth was unusually severe as this system is typically limited to about 50 percent DOD. Cycling at cathode current densities of 1, 5, and 10 masq cm and at both zero and 22 deg C allowed comparison to previously-evaluated lithium cells with other cathode materials. While the results generally were in agreement with data for 7- to 30-Ah LiLixCoO2 cells, two findings were unexpected. First, five to ten cycles could be obtained at the highest DOD before a continuously declining capacity fell below that obtained at 50 percent DOD, and useful cycles were attained thereafter. Second, at 37.5 DOD, twice the number of cycles were obtained at 22 deg C as at - 2 deg C. In all previous testing, no temperature dependence had been observed. The limited number of replicates in this test prompts caution interpreting the results.
- Electrochemical Energy Storage
- Inorganic Chemistry
- Physical Chemistry
- Electricity and Magnetism