Electrochemical performance of nickel/metal hydride batteries under unconventional conditions and degradation analysis

摘要

The charge-discharge performance and cycle stability of D size Ni/MH batteries at - 20 deg C, 25 deg C and 55 deg C were examined. The results show that the decline rate of Ni/MH battery discharge capacity a; - 20 deg C and 55 deg C are 12.1 percent and 13.6 percent and the average discharge voltage decreases by a value of 0.13 V and 0.96 V respectively, cycling stability declines obviously at various temperatures. The capacity degradation of Ni/MH batteries under low temperature is reversible, belonging to transient degradation and that of high and normal temperatures are not reversible, belonging to permanent degradation. Electrochemical impedance spectroscopy, scanning electron microscope and energy dispersive X-ray analyzer were introduced to study the main causes of cycling deterioration of Ni/MH batteries.