Study On The Formation Of Lead Acid Battery Based On (Basic) Lead Sulfate

Due to its advantages of high cost performance,safety and reliability,lead-acid battery has been widely used in the storage of automobile starting power supply,uninterruptible power supply,power supply and renewable energy.It has become an indispensable product in the production and life of human beings.Therefore,it is necessary to make this product more beautiful and cheaper through research.As the last process before the lead-acid battery leaves the factory,it directly affects the quality and service life of the battery.Due to the complexity of the conversion process and the confidentiality of the technology,there are few reports on the conversion research at present.In the past ten years,this laboratory has creatively studied a new recycling production technology of lead-acid batteries,which can directly produce lead sulfate and tetrabasic lead sulp Hate from waste lead-acid batteries without lead smelting.Then is directly used to produce new lead-acid batteries.At the same time,in order to make the production of lead-acid battery more convenient,the positive and negative alloy grid is also combined into one.In this way,the existing lead-acid battery production process changes from scratch,so we have to restudy the process so that we can use the new technology to produce high-quality batteries.The formation process is an electrochemical process.On the anode of lead sulfate,lead sulfate is reduced to porous"foam lead"by electrochemistry.On the positive electrode of the tetrabasic lead sulp Hate（4BS for short）,the reaction of 4BS with the electrolyte sulfuric acid to produce lead sulfate and their electrochemical oxidation to lead dioxide occurred simultaneously.Because lead sulfate and tetrabasic lead sulp Hate are poor conductor of electricity,it occur in the current collector grid and plate on the cathode oxygen fast response and slow lead sulfate oxidation reaction,And the hydrogen evolution reaction quickly on the plate with slow reduction reaction of lead sulfate influence into effect is good or bad.Therefore,this paper mainly explores the system from the two aspects of grille alloy and plate,and the main results are as follows:The existing lead-acid battery production technology uses different grids for the positive electrode and the negative electrode,which is not conducive to the cycle production of the battery,so we hope to combine the two kinds of grids into one.In order to determine which grid in the existing industrial grid is more suitable for dual-use,we used linear voltammetry to study the difference between the hydrogen and oxygen evolution potentials of the two grids at the same current density,and found that the positive grid is more suitable for dual-use.When the positive grid polarizes at a constant current,the ability to accept charge decreases with increasing current.As the current density increases,the surface of the corrosion layer changes from dense to loose,and the corrosion product particles increase.At the same current density,the over potential of the oxygen evolution reaction is lower than that of the hydrogen evolution reaction,so the oxygen evolution reaction on the positive electrode precedes the hydrogen evolution reaction on the negative electrode.（2）Taking into account the formation of the grid corrosion layer and the connection layer with the active material during the formation,as well as the time cost of the formation process,the oxygen evolution reaction and other factors,the laboratory-grade plate（4BS and Pb₃O₄ loadings are 0.6 g,0.06 g,respectively）.The formation step of the 4BS positive electrode is determined（three-electrode system）:constant current 0.4 mA·cm^-2for 4 hours,constant current 20 mA·cm^-2 for 15 hours,constant current 30 mA·cm^-2 for 5 hours,constant current 10 mA·cm^-2 for 5 hours,and constant current 5 mA·cm^-2 for 5 hours,and finally constant current 5 mA·cm^-2 for discharge.Cut-off potential is 0.8 V.According to this method,"three charge and two discharge"was carried out,and it was found that the content of Pb O₂slightly increased with the number of charging after each charge,the highest content could reach 77%,and the discharge capacity could reach 98 mAh·g^-1.（3）On the basis of the above research,the formation system of 4BS cathode industrial plate was studied.When the chemical conversion system is used for chemical conversion,the discharge specific capacity can reach 70 mAh·g^-1,and XRD analysis shows that the effect is acceptable.However,it may be because the reduction rate of Pb SO₄ to Pb is very slow,and the Pb SO₄ negative plate does not seem to adapt to the above system.The study found that reducing the current density can obtain better results（three-electrode system）:constant current-0.2 mA·cm^-2for 4 hours,constant current-5 mA·cm^-2 for 5 hours,constant current-15 mA·cm^-2 for 15 hours,constant current-5 mA·cm^-2 for 5 hours,and finally constant current 5 mA·cm^-2 for discharge.The cut-off potential is-0.8 V.Discharge capacity is 75 mAh·g^-1.When this chemical conversion system is applied to a self-made 4BS positive electrode and a Pb SO₄negative electrode full battery,the specific discharge capacity is calculated as 84mAh·g^-1 according to the quality of 4BS and 82 mAh·g^-1 according to the quality of PbSO₄,which is quite satisfying.