Study On Zn - PANI Secondary Battery In Electrolyte Aqueous Solution

Now with the world’s energy crises, and environmental pollution becoming increasingly serious, discover and create green pollution-free, safe and stable, low-cost, high-performance batteries for popularization is desperately needed. While zinc-polyaniline battery just meet the above requirements, but polyaniline battery technology is not yet mature, and far away from the large-scale industrialization. Therefore, the study of polyaniline battery and improve its performance is continually exploring. This paper has done the following work.In this paper, firstly, by the methods of cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and galvanostatic polarization to compare the electrochemical properties of the polyaniline electrode and the zinc electrode. Choose a better research electrolyte system between the sulfate (SO42-) aqueous systems and the chloride (Cl-) aqueous systems. Experimental results showed that the chloride (Cl-) aqueous systems can inhibit the degradation of polyaniline in a certain extent, and the zinc electrode corrosion phenomenon not easily occured in this system. On this basis, we explored the effects of pH and electrolyte composition ratio on the performance of the zinc electrode by the methods of CV, EIS and Three-dimensional NanoMap. The experimental results showed that electrochemical performance, stability and reversibility of the zinc electrode were the best when the electrolyte pH of about 4.0, ZnCl2 concentration was 0.20 mol dm-3, NH4CI concentration was 0.50 mol dm"3.In addition, various analysis methods including Fourier transform infrared (FT-IR) spectrometer, UV-visible (UV) spectrometer, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to compare the two kinds of polyaniline structure of different synthetic methods. It was found that the structure of polyaniline would not be affected by different synthesis ways. In the chloride (Cl-) aqueous systems, choose the best pH range and ratio for the polyaniline electrode. The results showed that the polyaniline electrode also had the best electrochemical activity when the electrolyte pH of about 4.0, ZnCl2 concentration was 0.20 mol dm-3, and NH4Cl concentration was 0.50 mol dm-3.Anu then, in this electrolyte, polyaniline was studied by CV and EIS.The stability and electrical properties of four current collectors:400 mesh stainless steel,50 mesh stainless steel,0.5 mm thin graphite paper and 0.3 mm thin graphite paper in the electrolyte (0.20 mol dm-3 ZnCl2+0.50 mol dm-3 NH4C1) were studied by CV, EIS, galvanostatic polarization. Zinc-polyaniline battery was assembled with the PANI mixture as cathode, the Zn plate as anode,0.20 mol dm-3 ZnCl2+0.50 mol dm-3 NH4Cl as electrolyte. According to investigating the effect of potential limits, time at constant potential, current density, separator and acid concentration, the final results showed that the best charging and discharging conditions for zinc-polyaniline battery was 0.7-1.7 V, 1min,50 mA g-1 at constant potential, absorbent paper as separator, and pH of about 4.0. The specific capacity of zinc-polyaniline battery could up to 78.2 mAh g-1. The coulombic efficiency of the zinc-polyaniline battery still remains at 100% after 1000 cycles of charge and discharge. At last, the zinc dendrite did not appear on the surface of the zinc plate.