Electrochemical performance of nickel/metal
hydride batteriesunder unconventional
conditions and degradation analysis①
hydride batteriesunder unconventional
conditions and degradation analysis①
(School of Chemical Engineering and Environmental Science , Beijing Institute of Technology,
National Development Center of Hi-Tech Green Materials, Beijing 100081, China)
National Development Center of Hi-Tech Green Materials, Beijing 100081, China)
Abstract: The charge-discharge performance and cycle stability of D size Ni/MH batteries at -20℃, 25℃and 55℃were examined. The results show that the decline rate of Ni/MHbattery discharge capacity at -20℃and 55℃are 12.1% and 13.6%,and the average discharge voltage decreases by a value of 0.13 V and 0.06 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.
Key words: Ni/MH battery; electrode materials; degradation; cycle life