The Degradation Characteristics and Mechanism of Li[Ni0.5Co0.2Mn0.3]O2 Batteries at Different Temperatures and Discharge Current Rates

Abstract

When lithium-ion batteries age with cycling, the loss of lithium inventory and active material may result in battery aging. The aging characteristics and mechanism of batteries under different cycle conditions differ. Therefore, battery cycle life tests were performed to explore the aging characteristics and mechanism of Li[Ni0.5Co0.2Mn0.3]O2 batteries. The results of the one-way analysis of variance show that the temperature has a slight effect on battery aging in the range of 25 °C–55 °C, but the discharge current has a great impact on battery aging in the range of 0.5C–2C. Battery aging mechanism can be analyzed by reconstructing charging voltage curves. But the hypothesis of the nondestructive method had not been verified through experiments. The hypothesis was verified through half-cell experiment, and the nondestructive diagnostic method was used to analyze the aging mechanisms of Li[Ni0.5Co0.2Mn0.3]O2 battery. The aging mechanism analysis results revealed that the main aging mechanism will change under different cycle conditions, therefore, the aging mechanism identification is necessary before establishing the battery life prediction model.