Preparation And Electrochemical Properties Investigation Of Carbon/Nickel Hydroxide Composite Material

Because of the growing energy shortage and urban environmental pollution and other issues, the development of battery-powered electric vehicles (Electric Vehicle) or hybrid cars (Hybrid Electric Vehicle) and other means of transport, is an effective way to solve this problem. Nickel-metal hydride (MH/Ni) battery is a new high-energy batteries, electric vehicle development application process power source of practical use. MH/Ni batteries are extremely nickel oxide electrode active material is Ni(OH)2. Ni(OH)2 depending on the nature of the crystal structure of the electrochemical activity, the interlayer stacking and structure defects can be improved performance of Ni(OH)2. Therefore, use Co doped, Graphene and carbon fiber composite increasing structure defects, reducing the crystallinity, to improve the Ni(OH)2 electrochemical properties. The detailed information of the dissertation is listed as follow:1. We prepared Co-doped α-Ni(OH)2 by Hydrothermal method using urea as precipitating agent, and pure α-Ni(OH)2 were prepared by hydrothermal preparation. The study found that doping Co of α-Ni(OH)2 is composed by nanorods and the morphology is flower sphere. REDOX peaks’ difference of cyclic voltammograms of Co doped α-Ni(OH)2 composites of is less than the that of the pure α-Ni(OH)2, discharge time is 1.5 times than pure α-Ni(OH)2. As the current density increased from 0.2 to 2 A g-1, pure α-Ni(OH)2 electric capacity attenuation by 67%, as the same time, Co doped α-Ni(OH)2 composites electrodes with current density increases from 0.2 to 5 A g-1, electric capacity is attenuatted 16%. Co doped α-Ni(OH)2 composites electrodes has more specific capacity.2. Preparation of different Co content doped α-Ni(OH)2, XRD, SEM, IR and CV testing technology, respectively, were adopted to characterize the structure and electrochemical properties. The results showed that the electrochemical performance of 1:1 content Co doped α-Ni(OH)2 composites is best, but the other content of Co doping of α-Ni(OH)2 nature than pure α-Ni(OH)2 still is better.3. Using ammonia as precipitant and hydrothermal prepared the pure β-Ni(OH)2 and Co doping β-Ni(OH)2. XRD, SEM and FTIR method were sued to characterize the samples morphology and functional groups. We can see from XRD prepared Ni(OH)2 is a beta phase, observed from the SEM the pure Ni(OH)2 and Co doping Ni(OH)2 composites are composed of flower ball by pieces. Cyclic voltammograms and discharge properties of Co doped β-Ni(OH)2 composites is better than pure β-Ni(OH)2. By alternating current impedance test, we can see radius of the Co doped β-Ni(OH)2 composites less than pure β-Ni(OH)2 in the high frequency region, indicating that the Co doping β-Ni(OH)2 composites electrodes compared with pure β-Ni(OH)2, has a low resistance and better capacitive. Compared witha-Ni(OH)2, the discharge time of Co doped α-Ni(OH)2 composites is 2.4 times more than Co doping β-Ni(OH)2, CV curve of Co doped α-Ni(OH)2 has good symmetry, but Co doping β-Ni(OH)2 composites of symmetry is poor. So Co doping α-Ni(OH)2 has very good reversibility, and Co doping β-Ni(OH)2 is worse.4. Hydrothermal method is used to composite graphene with α-Ni(OH)2, the quality ratio is 1:20 and 1:40. XRD, SEM, IR and CV testing technology were used to characterize the structure and electrochemical properties. Studies have shown that with the change of the current density, mass ratio of 1:40 graphene/α-Ni(OH)2 complex electric capacity attenuation is less than 1:20. After compound graphene electrochemical performance is improved.5. Use the method of electrostatic spinning preparation of carbon fiber, and to determine the concentration of the sol, voltage and receiving distance preparation technology parameters. Using XRD, IR and Roman confirmed that the preparation of the fiber is indeed carbon fiber. Using hydrothermal composite carbon fiber and α-Ni(OH)2, the α-Ni(OH)2 lamellar structure uniform grown in carbon fiber. Making the electrochemical test for carbon fiber/Ni(OH)2, cyclic voltammograms compared with pure α-Ni(OH)2 has obvious oxidation and reduction peaks.