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Intermittent operation of the aprotic Li-O2 battery: the mass recovery process upon discharge interval

Research paper by Ding Zhu, Lei Zhang, Ming Song, Xiaofei Wang, Rui Mi, Hao Liu, Jun Mei, Leo W. M. Lau, Yungui Chen

Indexed on: 11 Jun '13Published on: 11 Jun '13Published in: Journal of Solid State Electrochemistry



Abstract

The intermittent operation of the aprotic Li-O2 battery is systematically studied in this paper. A combined study of the battery charge retention and the electrolyte stability to O2 suggests a low self-discharge rate of the Li-O2 battery, which is a prerequisite to achieve desirable intermittent discharge performance. The battery under intermittent operation exhibits significantly improved discharge performance as compared to the continuously discharged one. It is found that the capacity output is directly associated with the time interval between two discharge steps and with the capacity limit for each discharge step. The open-circuit potential and linear scan voltammetry analyses confirm that a “mass recovery” process, corresponding to the concentration relaxation of the oxygen which is available at the cathode, proceed during the discharge intervals. In the “mass recovery” process, an increased amount of O2 homogeneously redistributes at the electrolyte/carbon interface at both sides of the electrode, which relieves the O2 transport limit, enhances the availability of O2 and the utilization of carbon material for the cathode, and thus significantly improves the discharge performance of the aprotic Li-O2 battery.