Study On The Preparation And Properties Of Tetra-basic Lead Sulphate Crystals

In recent years, with the rapid development of communication industry and electriccar, lead-acid battery raised the research up once again. It’s looking forward to appearthe lead-acid battery with higher specific energy and power and longer life cycle. Inorder to solve the initial capacity loss of it, the tetra-basic lead sulphate （4BS） asadditive of positive lead paste was confirmed as one of the effective solution to preventthe premature capacity loss.In this paper, three kinds of preparation methods: hydrothermal method,ball-milling method and hydrothermal combined with ball-milling method was used tosynthetize4BS. And the prepared4BS was added to the positive paste as seed, throughthe high temperature curing, formation process, prepared the positive plates, plates afterformation, and then assembled into the simulate cell. The morphologies, structures,compositions and particle size of4BS were characterized by scanning electronmicroscopy （SEM）, X ray diffraction （XRD） and particle size analyzer analysis.Through the simulate battery method of discharge test, coulomb efficiency of4BSadded to the positive plate is studied with the performance of the battery, and study onthe initial capacity test, cyclic voltammogram by simulate battery on theelectrochemical properties of4BS.First,4BS was prepared by hydrothermal method in raw materials of differenttemperature and time. The results show that, when the reaction temperature and time are130oC and5h, pure lead oxide and H₂SO₄produced4BS with the highest and goodmorphology. The distribution of4BS crystal is uniform, but through the analysis of4BSparticle size, which was obtained using hydrothermal method, distribute range ofparticle size is wide, about0⁷0μm. In the hydrothermal method, particle size is notdown to standard10μm. In order to reduce the particle size, the ball-milling methodwas chosed. The results showed that, when the ball-milling time is3h, the content of4BS is the highest, and the morphology of pure lead oxide reaction with PbSO4is better.The particle size distribution is between0¹5μm, although it could satisfy therequirements, take the price of PbSO4into account, the feasibility of this method is not high with the cost of production enterprises. As the method to prepare4BS combinedwith the disadvantages of the above two kinds of methods, hydrothermal combined withball-milling method is adopted to make up for the defects of the former two methods.The results show that the hydrothermal reaction temperature is130oC for5h andball-milling time is3h, higher content of4BS is pure lead oxide and H₂SO₄solution.The distribution of the SEM characterization is uniform. The particle size distribution isrelatively concentrated and average particle size is10μm, illustrated by the fact that4BS prepared by this method is the best.For the4BS crystal, the same quality of the positive plate weighing was added tolead-acid battery in three preparations, respectively. XRD show that the positive platesgenerate4BS, and4BS prepared by the hydrothermal combined with ball-millingmethod is highest in the content of4BS on positive plates. The particle size was smallercompared with other positive plates. With4BS crystal as addition, its particle size has acertain influence on the formation of plates of4BS particle size, as4BS crystal size issmaller, generated in the plate of4BS is smaller. It indicates that the formate skeleton ofactive substances becomes stronger with the increase of lead-acid battery performance.By the initial capacity test of simulate cell, relative to the initial capacity of simulatebattery use the method that does not add4BS initial capacity of crystal it’s slightlylarger, the initial capacity of the battery does not have too big effect. In the dischargecurves of2h efficiency of simulate battery,4BS is generated using pure lead oxide andH₂SO₄solution reaction conditions lead to long time, which is about153min. Andcompared to the other groups that add4BS, the material has the maximum coulombefficiency. In the cyclic voltammogramof electrode formed by adding4BS, thereduction peak potentials is positive compared to other electrodes of reduction potential,especially the reduction peak is highest. The discharge performance of4BS battery bythis preparation method is the best, and the reduction potential and the oxidationpotential have the minimum value. The cell with the best relatively reversible charactersis obtained.