Study On Hydrogen Storage Property Of Nickel Nanotubes And AC Impedance Of Ni/MH Batteries

Nowadays, MH-Ni batteries have been served as important resource for various equipments, such as electric vehicle,portable computers and mobile telephones. To heighten the hydrogen storage of negative-electrode materials can increase the property of MH-Ni batteries. As nanotubes have hydrogen storage property , nickel nanotubes were prepared and the electrochemical properties were tested in this experiment.Nickel nanotubes were prepared by electrochemical deposition on the anodic aluminum oxide (AAO) templates. The templates and the nickel nanotubes were characterized by SEM, TEM and electron diffraction. The prepared nickel nanotubes are approximately 20nm in an outer diameter. The length is approximately 1μm. Further investigation on the electrochemical performance of nickel nanotubes was studied. The results showed that nickel nanotubes used as microelectrode have higher Hydrogen Storage Property than nickel powder.Cycle life is one of significant standards of evaluating battery performance. It is so difficult to accurately test battery's cycle life if we do not destroy the battery that there is practical significance for researching a method of forcasting the battery's cycle life.In this experiment, the AC impedance at different SOC and cycle life were tested for four different electrolyte quantity MH-Ni batteries. The relationship between cycle life and impedance parameters was studied. The results showed that the AC impedance spectras of MH-Ni batteries at different states all comprise of a semicircle at high frequency and a line at low frequency. The impedance parameters have some disciplinarian during discharging and cycling. By comparing the cycle life and the impedance parameters, the value of Rt has certain relationship with cycle life of MH-Ni batteries: the larger of the value of Rt, the shorter the cycle life.