Technology of Zinc Electrode Construction of zinc silver oxide battery via Pasting Method.

Zinc-Silver oxide battery is one kinds of high energy batteries with power density of 50-120 Wh/Kg, high rate of discharging (10 to 15 times of nominal capacity) and insignificant polarization. This kind of battery has wide spreading applications in those systems that have high energy and low volume of electrical power source such as military and aero-space ones. Secondary zinc-silver oxide battery is designed and manufactured in two different types of dry discharge and dry charge. In former the active material of electrode is in the form of inactive silver and zinc oxide, and after electrolyte injection this cell will be ready for preliminary charging reactions. Consequently, after several formation cycles, it is turn of discharging with final certain current and reaching to the complete capacity. In the dry discharge secondary zinc-silver oxide battery, the active material of anodic electrode is zinc oxide. During the discharging reaction, the anodic electrode produces Zn(OH)4 2- zincate ion that is soluble in the alkaline electrolyte KOH, therefore it enters to the electrolyte phase. In these kinds of batteries the cellophane separators are wrapped around the zinc electrodes in order to prevent the zincates ions migration. Also the membrane avoids the penetrations of Ag(OH)2 - or Ag(OH)3 2- -the producing ions of the silver cathodic electrode- towards the zinc electrodes. In zinc electrode manufacturing, the polymeric additive factors are also inserted to the active materials of electrode in order to enhance the adherence of zinc to the electrode grid, and also prevent the morphology and shape change of electrode during the charge and discharge cycles. For designing this kind of battery with high discharging current, it is better to decrease the thickness of electrodes and increase their numbers in definite volume. Since the effective surface of reaction area is enhanced and the density of discharge current is decreased, so the average of discharge voltage and the total discharge current of the cell will be increased. In industrial manufacturing, all efforts are utilized in producing the electrodes with less thickness and more consistency. Rate increasing of zinc electrode producing and improving the consistency in its manufacturing cause the production of electrodes with exactly the same operations. The technology of zinc oxide electrode construction via pasting method is required to reach to this goal. Hence the paste solution should be selected in such a way that can provide the adherence and connectivity of the active material to each other and to the electrode grid, also chemically and electrochemically not disturb the operation of the anode. As a result a series of researching actions are performed with the following aims: Selecting the appropriate paste making material in order to apply as a supporting agent of the active material of anode. Utilizing the suitable porous making material in order to enhance the effective surface of anodic electrode and reduce the concentration polarization. Applying the proper material to inhibit the hydrogen and oxygen releasing of the surface of the electrode during the charge and discharge processes. Using the convenient material to decrease the corrosion and self discharging of anode in alkaline medium.