Research On Anode Process And Preparation Of Anode Materials Based On Leadmethanesulfonate System

With the continuous development of new energy vehicles,people’s demand for lead-acid batteries is increasing.However,it is followed by a series of problems caused by improper recycling of lead-acid batteries.Therefore,it is urgent to develop a clean,efficient and practical lead recycling method.At present,there are two main methods for recycling lead-acid batteries.The first is traditional fire treatment,but this method has a low recovery rate and will cause environmental pollution.The second method is wet treatment.In recent years,extensive research has been carried out on the wet treatment of waste lead-acid batteries allovertheworld and methanesulfonic acid has become a research hotspot due to its excellent properties.In this paper,lead methanesulfonate is selected as the electrolyte to explore the influencing factors and changing rules of the anode process.Onthisbasis,the anode catalystswith low overpotential ofoxygen evolution reaction（OER）are prepared,which caneffecitively avoid the generation of Pb O₂and thus reduce the electrolytic energy consumption.The main research contents and results of this paper are as follows.（1）By using Ti Ir Ta electrode and Ti Ir Ru electrode as working electrodes,the effects of phosphoric acid dosage,Pb²⁺concentration,methanesulfonic concentration and temperature on anode process were explored.The experimental results show that these factors have basically the same effect on the anodic process of Ti Ir Ru electrode and Ti Ir Ta electrode.With the addition of phosphoric acid,the precipitation of Pb O₂decreases or even disappears.In the case of adding 4 g L^-1phosphate phosphoric acid,the increase of Pb²⁺concentration is not conducive to OER.When the concentration of methanesulfonic acid is in the range of 0.6-1.4 mol L^-1,the increase of methanesulfonic acid is beneficial to OER.And as the temperature increases,the catalytic activity for OER increases.However,the two electrodes are slightly different.The OER performance of Ti Ir Ru electrode increases with the increase of phosphoric acid content,while the OER performance of Ti Ir Ta electrode increases first and then decreases with the increase of phosphoric acid content.（2）Mn_xO_y@Ru O₂was obtained from Mn-BDC through Ru doping and oxidation steps.The electronic coupling between Mn and Ru makes the electron cloud density shift,which greatly promotes the OER.The OER overpotential of Mn_xO_y@Ru O₂is only 175m V at a current density of 10 m A cm^-2in 0.5 mol L^-1H₂SO₄,and only 375.6m V is required for 25 m A cm^-2electrolysis in lead methanesulfonate system.Then,the preparation conditions of catalyst were optimized.When the mass ratio of Mn-BDC and Ru Cl₃is adjusted to 1:1,and the oxidation temperature is 450°C,the Mn_xO_y@Ru O₂electrode has the best catalytic activity for OER and the ability to reduce the precipitation of lead dioxide.（3）Co Mn-MOF-74 was used as a precursor for Ru doping and annealing oxidation,which could better maintain the crystal structure of MOF.Co Mn-Ru O₂has higher activity and better stability.The catalysts were prepared by using Co-MOF-74,Mn-MOF-74 and Co Mn-MOF-74 as precursors for comparison.It is found that the overpotential of Co Mn-Ru O₂is only 258.3m V at a current density of 10 m A cm^-2in 0.5mol L^-1H₂SO₄,which greatly reduces the precipitation of Pb O₂.It is worth mentioning that galvanostatic electrolysis is performed in sulfuric acid for 20 hours and the overpotential only increases by 5.5%,indicating that it has good stability.