Studies On The Performance Of Secondary Zinc Electrode In Alkaline System

Zinc is broadly used as negative electrode material for many cell systems, because of its good electrochemistry properties, favorable technological and economic features. But it is hindered that secondary zinc battery is used on a large scale, because of the problem of the secondary alkaline zinc electrode. Main reasons are as follow:1. A problem is the formation of zinc dendrite during charging and overcharging of the zinc electrode causing short circuiting by penetration through the separator.2. During charge-discharge cycle, zinc active material can migrate across the face of the electrode. These migrations processes result in regions which have very little or no zinc, and regions of the electrode with dense and nodular zinc. This will lead to capacity loss.3. Due to the non-uniform of face of zinc electrode, a lot of micro batteries will be formed in the zinc electrode. It will wear away zinc active material.4. Under certain condition the zinc electrode tends to the passivation in the discharge phase. The passivation reduce the usage of zinc active material and capacity.This paper is mainly to find solutions to above problems in order to obtain long life zinc electrode by these methods that electrode additive and electrolytic additive add to zinc electrode. The effect of two additives on zinc electrode were studied in the paper, Electrode additives: calcium, PbO, Bi203, Sn02; electrolytic additives: KF+K2C03, two organic additives. The experimental results as follow: ＋1. In alkaline solution, the performance of calcium zincate prevailed that of the mixture of zinc calcium. The solubility of this complex is less than that of ZnO, and the lower zinc species solubility leads to a slower rate of redistribution, a diminution of zinc dendrite and migration, thereby extending the cell cycle life.2. The proper addition of metal oxides (PbO, Bi203, Sn02) can improve the performance of zinc electrode, such as the morphology of zinc deposit, zinc dendrite, zinc migration and so on.3. It can reduce the solubility of zinc in the alkaline solution that KF, K2CO3 substitute for a portion of KOH in secondary zinc battery, so this inhibit the dendrite growth of zinc, deformation of zinc electrode, and prolong the cycle life of zinc electrode.4. through the absorption in active material of surface of zinc electrode, sulfocarbamide, C16H33(CH3)3NBr will suppress zinc deposit on the situation. This inhibit the dendrite growth of zinc.