| The lead-acid battery is an extensively used secondary battery.The new product ---- VRLA(valve regulated lead acid ) battery comeforth with the development and demands of environment protection and resources utilization. VRLA battery has two kinds of technology : AGM(absorptive glass-microfibre) and GEL technology. In recent years, the gel technology and manufacture technology of lead oxide of VRLA battery get recognition gradually. In this paper, two main aspects have been studied as follows: the performance of gelled electrolytes and effects of them on lead electrode in the gelled lead-acid battery; effects of bismuth on the lead-acid battery with or without gel.In the first part of this paper, cyclic voltammetry (CV), linear scanning voltammetry (LSV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy(SEM), transmission electron microscopy (TEM) and other methods have been used to study the influences of the type and the content of gelling agent, the concentration of sulfuric acid used to prepare the gelled electrolyte and the existence of inorganic ions on the performance of gel and the electrochemical behavior of lead electrode. The optimum conditions for preparing the gelled electrolyte have been researched and the various influential factors discussed and analyzed.The gelling performance of gelled electrolyte prepared by K*IVsystem and si 1 ica soot are studied and compared with the traditional gelled electrolytes prepared by common silica solution and super-pure silica solution. Influences of the type of gelling agent used for preparing the gelled electrolyte on the gelling state of gelled electrolytes and the behavior of lead negative electrode have been discussed. The coexiting ions, surface state of the gelled electrolyte, the formation and texture of gel are investigated so as to find a better gelling agent. The experimental results demonstrate that the K* system and silica soot are suitable for preparing gelled electrolytes. The gelled electrolyte thus prepared has much better surface structure and electrochemical performance than that prepared by the other two gelling agents.The gelled electrolytes used for gelled lead-acid battery are prepared by blending silica soot as gelling agent with sulfuric acid according to a certain proportion. Influences of the sulfuric acid concentration on the gelling and electrochemical performances of gelled electrolyte have been studied. Experiments show that the thixotropy of gelled electrolyte is increased as a function of the concentration of H2S04. In addition, sulfuric acid concentration also affects to a certain degree the electrochemical behavior of negative electrode.The content of SiO,. and the viscosity of gel are important factors affecting the capacity of batteries. The viscosity and thixotropy performance of Si02 sol containing different SiO.- have been determined. Influences of the content of Si02 contained in the gelled electrolyte on the electrochemical behavior of Pb electrode and the structure of gelled electrolytes have been discussed in detail. The result of CV indicates that the oxidation and reductioncapacity of lead electrode is decreased with increasing SiO^ content. The reaction resistance is increased as a function of the content of Si(X at open-circuit potential(0. C. P), as show by impendance experiments.Effects of the content of IT ions in gelled electrolyte on the behavior of lead electrode have been discussed preliminarily. The results of experiments show that the current and capacity of oxidation and reduction of lead electrode is increased with increasing K" content.Electrochemical behavior of lead electrode in sulfuric acid and gelled electrolyte have been investigated by means of CV, LSV and EIS. The results of CV and EIS demonstrate that the oxidation peak potential of lead electrode is shifted slightly to the negative side in gelled electrolyte, implying that gel contributes to the oxidation of Pb into Pb2*. LSV studies show that the current of hydrogen evolution...
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