Study On Preparation And Electrochemical Characteristics Of Ni(OH)₂ Coated With CoOOH

With the seriously environmental pollution and energy shortage, many countries have begun to research and develop electric vehicles. Ni/MH battery has been highly evaluated due to high energe density,good security and no pollution. Because Ni/MH battery is limited by the positive electrod, it is necessary to do research on high-performance cathode materials.Ni(OH)2 coated with CoOOH was prepared by liquid reaction .The influnces of Co content, pH value, temperature and NaClO addition on Ni(OH)2's reversible performance were studied by orthogonal test, and the optimal preparation condition was obtained comparing with different Ni(OH)2 by CV curves :wCo= 0.025, pH =12, 75℃,VNaClO =7cm3 .The results showed that uniform CoOOH conductive network on the surface of Ni(OH)2 was formed under the best conditions, and the conductivity of Ni(OH)2 was improved.The morphology and crystal structure of different conditions of Ni(OH)2 coated with CoOOH were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that CoOOH layer on the surface of Ni(OH)2 was uniformed. The crystal structures of Ni(OH)2 belonged toβ-Ni(OH)2, and the FWHM of diffraction characteristics peaks became wider .The high rate performance and specific capacity of Ni(OH)2 coated with CoOOH were studied by means of constant current charge-discharge test. The results showed that CoOOH coating layer could reduce the internal resistance, improve the performance of the battery, reduce the capacity declining of the high rate and increase the rate of capacity maintainance.