Synthesis And Electrochemical Properties Of Battery Grade Lead Oxide Based On A Lead-Oxygen Fuel Cell

High quality lead oxide is the essential raw material of the manufacture of advanced lead-acid battery, which is widely used in large amount of fields, such as starting power supply and power sources of electric vehicle. In order to counter the serious pollution and high energy consumption in traditional lead oxide production process (Shimadzu ball milling method and Barton pot process), this paper reports a new green method of high purity lead oxide. Lead anode and oxygen cathode are assembled together to form a lead-oxygen fuel cell. Continuous electricity, as well as electrolyte with high concentrations of lead oxide are obtained. Lead oxide is crystallized from pregnant liquor. Around the electrode process in lead-oxygen fuel cell and the crystallization process of lead oxide, the main researches and results in this paper are listed as follows:First of all, we research on the anodic process of lead in sodium hydroxide with three-electrode method. The effect of the concentration of sodium hydroxide, electrolyte temperature, the concentration of lead oxide and lead additives on the anodic process is investigated by linear sweep voltammetry, impedance spectroscopy, cyclic voltammetry, constant current discharge and tafel electrochemical tests. The research indicates that the lead anode has the highest reaction activity when the electrolyte is 30% sodium hydroxide at 80 ? with 0.2 mol·L-1 chlorine as anode additives.Then we sduty the influences of the concentration of sodium hydroxide, electrolyte temperature, the concentration of lead oxide and lead additives on the oxygen cathodic process. The results show that the oxygen cathode has the highest reaction activity when the electrolyte is 30% sodium hydroxide at room temperature. The addition of anode additives has little effect on oxygen cathode.Apart from the electrochemical properties of lead-oxygen fuel cell, crystallization and recycling process of sodium hydroxide-lead oxide electrolyte is also studied. The result shows that the average potential of lead-oxygen fuel cell is up to 0.5 V at the discharge current density 35 mA cm-2 in the 30% sodium hydroxide with additional 0.2 mol·L-1 chlorine at 80 ?. After the sodium hydroxide-lead oxide electrolyte is cooled down and lead oxide is crystallized, the recycled mother liquor sodium hydroxide is used as electrolyte once again. The discharge potential keeps stable in next few cycles.At last, the synthetic lead oxide is investigated by SEM and XRD test. One thing, the results show that the lead oxide crystal structure is affected by sodium hydroxide concentration and cooling rate. The other thing, the surface morphology is affected by stirring speed. Alpha-lead oxide, beta-lead oxide and the combination of the two are obtained by crystallization and all three of these are treated as positive electrode, respectively. The performance of these synthetic lead oxide, alpha-lead in particular, show better electrochemical activity and greater stability than those from traditional methods.