Lead Sulfate As Lead-acid Battery Electrode Active Material Synthesis And Performance Study

Lead sulfate is the electrode active material of lead-acid batteries.It is formed when the lead-acid battery is discharged.When it is charged,it is converted into PbO₂in the positive plate and converted into Pb in the negative plate.Previous work in our laboratory has demonstrated that chemically synthesized PbSO4 is electrochemica lly active and has good performance when used directly as an electrode active material,and does not require long-term curing like industrial lead powder plate,thereby shortening plate manufacturing time,reducing lead-acid batteries production costs and energy consumption.On the other hand,the recycling of spent lead-acid batteries will generate large amounts of low-value by-product ammonium sulfate,which has led us to two research motives to achieve the recycling of lead-acid batteries:?1?The loss of lost electrochemically active lead sulfate from spent batteries is converted into electrochemically active lead sulfate.?2?The formation of by-product ammonium sulfate is minimized.For these reason,this article explored three ways to synthesize lead sulfate.?1?Direct reaction of PbO with ammonium sulfate.It was found that?-PbO can react directly with ammonium sulfate at room temperature,but the product was one-base lead sulfate?1BS?,when the temperature is raised to 110°C,the reaction can obtain lead sulfate,but there was a very small amount of impurities 1BS.?2?Indirect reaction of PbO and ammonium sulfate.Experiments showed that?-PbO reacts with ammonium acetate to produce clear lead acetate solution,which in turn reacted with ammonium sulfate to produce pure lead sulfate?hereinafter referred to as S2?.?3?Indirect reaction of PbCO₃ and ammonium sulfate.Lead carbonate reacted with ammonium acetate to produce clear lead acetate solution,which is then reacted with ammonium sulfate to produce pure lead sulfate?hereinafter referred to as S3?.In order to compare their electrochemical properties,the best electrode formula was studied in this paper by using the industrial lead sulfate?hereinafter referred to as S1?from the reaction of?-PbO and sulfuric acid.Then the positive and negative electrodes were made according to the optimum electrode formulation.It was found that when lead sulfate is used as positive active material,the discharge capacity of S1,S2 and S3 can reach 90 mAh·g^-1 when the discharge depth is 100%under the current density of 100 mA·g^-1 in the 100th charge and discharge cycle.When three samples were used as negative active material for lead-acid batteries,their discharge capacities were all 100 mAh·g^-1 at the 100 mA·g^-1 current density at100%discharge depth.S2 can reach 108.2 mAh·g^-1 slightly.In addition,the cycle life of S1 reached 580 cycles,and the cycle of S2 and S3 reached 680 cycles,indicating that the three kinds of lead sulphate serve as anode material with excelent cycling stability.Therefore,the lead sulfate obtained in this experiment is an excellent negative electrode active material.