Cycle life evaluation of 3Ah Li{sub x}Mn{sub 2}O{sub 4}-based lithium-ion secondary cells for low-earth-orbit satellites. II. Harvested electrode examination.
Lithium-ion batteries are a candidate for the energy storage system onboard low-earth-orbit satellites. Terrestrial experiments are able to capture the performance degradation of cells in orbit, therefore providing the opportunity for lifetime investigations. The lifetime performance of 3 Ah commercial Li{sub x}Mn{sub 2}O{sub 4}-based pouch cells was evaluated in a matrix of different cycling depths-of-discharge (DODs: 0, 20, 40%) and temperatures (25, 45 C). Aged cells were disassembled and the electrochemical performance of harvested electrodes investigated with two- and three-electrode pouch cells. The positive electrode had a larger decrease in capacity than the negative electrode. Both the positive and negative electrode contributed to the increase of cell impedance measured at high states-of-charge (SOCs). The data at low SOCs indicated that the increase of cell impedance was associated with the positive electrode, which showed a significant increase in the magnitude of the high-frequency semi-circle. This SOC-dependence was observed for cells cycled for either extended periods of time or at higher temperatures with a 40% DOD swing. Low-current cycling of positive electrodes revealed a change in the second potential plateau, possibly reflecting a structural change of the Li{sub x}Mn{sub 2}O{sub 4}. This could impact on the electrode kinetics and provide a possible explanation for the SOC-dependent change of the impedance.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- Japan Aerospace Exploration Agency
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 985110
- Report Number(s):
- ANL/CSE/JA-62041; TRN: US201016%%1785
- Journal Information:
- J. Power Sources, Vol. 185, Issue 2008
- Country of Publication:
- United States
- Language:
- ENGLISH
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