Research Of The Minitype Zinc-Air Battery

The great efforts are made worldwide to develop battery systems having high specific energy. The demand for such systems has risen dramatically in recent times, particularly in connection with electric traction, the storage of electrical energy from photovoltaic installations and the operation of portable devices. Among all batteries, because of its steady performance, source of raw material and low-cost, the study and the development of zinc-air battery is paid more and more attention. Because of their high specific energy and inexpensive and environmentally benign materials, Zn-air batteries are promising energy storage devices.Research of zinc-air battery in this thesis includes: optimum process of air electrode preparing, assembly of button cell, design and assembly of cylinder cell. The performance of air electrode has a decisional effect on zinc-air battery whose development goes with improvement of air electrode. In this experiment, we focus on optimum of catalyst preparing of the cathode. The effects of pyrolysis temperature, ratio of active carbon and acetylene black, carbon pretreatment and content of Mn(NC>3)2 (vs. carbon support) on air electrode performance are investigated through steady polarization .The results show that under the follow conditions: pyrolysis temperature 270癈,active carbon and: ethyne black=9:l, carbon pretreated with HNOs, 7.18% Mn(NO3)2(vs. carbon support) catalyst can exhibit the best performance. In order to improve the electrocatalystic performance of MnO2, Pb(CH3COO)2 , La(NO3)3-6H2O and Ce(NO3)3-6H2O are chosen as additives of MnCVC air electrode . Electrochemical performance of the electrodes is studied by current-potential polarization curves. The results show: Adding 7.5% content of Pb(CH3COO)2 can best improved the performance, at the typical current density 20~50mA/cm2 of air-metal battery, air electrode potential can be improved by 30~50mV. Ce additives showed better performance than La. When adding 10% content of Ce(N03)3-6H2O can best improved the performance.At the typical current density 20-5 Om A/cm2 of air-metal battery, this air electrode potential can be improved by 30-60mV. AC impedance properties of those air electrodes are investigated .The impedance spectra are analyzed using an equivalent circuit containing two Nerstain diffusion terms. The simulated data are also discussed. Those additives can decrease the charge-transfer resistance and oxygen diffusion resistance.As to button zinc-air battery, we improve its zinc anode structure through granulation process. Battery discharge test using different type of zinc powder shows that this anode structure has a positive effect on utilization ratio of zinc anode, the best utilization ratio is about 90%. According to structure of alkaline manganese cell, cylinder zinc-air battery is designed. Air electrode is outside, zinc anode whose structure as same as button zinc-air battery in the center .By R6 type battery testing method, this cylinder zinc-air battery can discharge 19 hours. Its anode utilization ratio is 80% or so.