Study On Preparation And Electrochemical Performance Of Novel Zinc Electrode Of Zinc-silver Battery

The advantages of zinc silver battery have high specific energy, highspecific power, stable discharge voltage platform, high rate dischargeperformance. It applied widely in national defence and military. At present theresearch institute for its development level improved greatly. So this silver zincbattery specific energy and high rate discharge performance were paid attentionwidely because of the rapid development of further requirements.The foamed silver with the large aperture is used for the collector. Thedendrite shape of the zinc cathode is prepared by electrochemical deposition.Through some key parameters optimization, the structure of zinc electrode wasadjusted, while the discharge specific capacity increased. The apparent influencesof electrodeposition process on discharge performance were studied. Influencingfactors have the stirring rate, temperature, potassium hydroxide concentration,current density and deposition time, on which the stirring rate and temperaturehad the greatest impact. With stirring conditions zinc morphology is mostly largegranular and thick sheet; Without stirring condition zinc structure isdendrite.With the low temperature zinc is granular. Temperature is20℃, zinc isdendrite shape. With the temperature increase, the zinc morphology transforminto the dense mossy. The specific surface of the mossy is small. It made againstto the discharge. The best electrodeposition process conditions are determined:no stirring, temperature was20℃.Potassium hydroxide concentration was280g·L-1, the current density was100mA·cm-2, deposition time was20min.The article study five different apertures of foamed silver which were usedfor the collector. The increases of pore size of foamed silver contribute to theformation of zinc dendrites and zinc dendrite extending to the three-dimensionaldirection. When the aperture of the foam silver are1200μm and3000μm ascollector, the discharge specific capacity reached730mAh·g-1(3C)).Thedischarge specific capacity can reach to more than550mAh·g-1(10C).Thebubble diameter of foamed silver is used for collector, large current dischargeperformance of zinc electrode was excellent.Further research focused on the method of reducing the thickness of zincelectrode. One is preparing zinc electrode by the paste forming method, afterformation thickness of zinc electrode is reduced. When the aperture of foamsilver collector is1200μm, the discharge specific capacity is largest, reaching340mAh·g-1.In the further it will improve the process. Another is to reduce thethickness of foamed silver collector. Foamed silver will have a certain pressure to reduce the thickness of the collector itself thickness. Zinc electrode is preparedby electrodeposition. When the aperture of foam silver collector is580μm,thickness of zinc electrode is about0.6mm. The discharge specific capacity islargest, reaching500mAh·g-1. The capacity of the zinc electrode improved15%than it prepared in factory.