Study On The Properties Of Zinc Electrode Of Alkaline Air Battery

The influence of technical parameters of preparation and electrolyte additives on the electrochemical performance of zinc electrode were investigated in this paper by hydrogen generation, polarization experiment, data fitting in weak polarization region, surface tension test, discharge test and SEM, in order to solving the problems of zinc electrode such as passivation and erosion. The zinc air battery with high discharge capacity and active material utility was prepared here. A new technique approach was provided for improving electrochemical performance of zinc electrode.Results show that the active material utility of zinc electrode increases from 30.27% to 40.4% under the technical parameters with acicular zinc powder, copper net coating with nickel as current collector, PTFE (8wt%) + CMC-Na (2wt%) compound binder, 250KN forming pressure and lmm electrode separation, when discharging at 25℃ and 60% relative humidity. Acicular zinc powders can enhance the intensity and porosity of zinc electrode. The zinc particle size mainly influences the discharge capacity of low-voltage phase. Using the mixture of the hydrophobic PTFE and the hydrophilic CMC-Na as zinc electrode binder can improve both the adhesive property and wettability of zinc electrode. Copper net coating with nickel as current collector has good conductivity and corrosion resistance. The zinc electrode has high intensity and the original shape of zinc powder is maintained, when the anode prepared under 250KN forming pressure. Zinc air battery of lmm electrode separation ensures the anode to have enough bulgy space. And the resistance of electron transfer is proper under this condition. The temperature and humidity can influence the electrical conductivity of the electrolyte to some extent.Through absorptive effect, anionic surfactant sodium dodecyl benzene sulfonate(SDBS) improves the surface morphologies of the zinc electrode during the discharge process. The corrosion and passivation processes have been restrained at one time. The active material utility of zinc electrode is increased from 40.4% to 56.4% and the corrosion rate is increased to 84.84% at 4g·L^-1 SDBS optimum concentration. Although nonionic surfactant Tween-20 has activation effect on zinc electrode, it has little influence on corrosion and discharge capacity. Zinc electrode has much higher discharge capacity in ST compound electrolyte than in singleness SDBS or Tween-20 electrolyte. Its active material utility of zinc electrode is as high as 80.7% at the optimum concentration (0.001g·L^-1Tween-20+0.4g·L^-1SDBS). The corrosion rate is 83.26% which is much closer to the one of single SDBS system through data fitting in weak polarization region. There is an obvious synergistic effect between SDBS and Tween-20. The saturated surface absorption of SDBS on zinc electrode in the combined electrolyte is reduced obviously due to the ingression of Tween-20 into the blended micelle. The optimum concentration of SDBS is decreased from 4g·L^-1 while used solely to 0.4g·L^-1 while mixed SDBS and Tween-20 together. The adsorptive distribution becomes more uniform. The passivition and corrosion of zinc electrode have been postponed effectively.