Performance Of Tetrabasic Lead Sulfate Prepared In Situ In The Positive Electrode Of Lead Acid Battery

Earlier studies have shown that one of the main causes of lead-acid battery failure is the softening and shedding of the positive lead paste.Tetrabasic lead sulphate（4PbO·PbSO₄,4BS）can form positive electrodes with good properties because of their special morphology and chemical structure,which can effectively reduce this issue.Industrially,a positive electrode manufactured using industrial lead powder requires a long time of curing under high temperature and high humidity conditions to obtain a positive electrode active material mainly composed of 4BS.The problems caused by this method are not only the energy consumption and the occupied space of the factory,but also low electrode performance,especially process inconsistency.For this reason,we have done the following research to improve the electrochemical performance of the battery:（1）Using PbO and PbSO₄ as raw material electrodes to react in situ in positive electrode to obtain 4BS positive electrode to enhance the binding force inside the electrode.It was found that when the reaction time is 1.5 h,4BS is completely fod,and the particles of 4BS crystals gradually became larger with the prolonging of time.The discharge capacities of the electrodes at 1.5 h,6 h,and 12 h at discharge depth（DOD）of 100%and discharge current density of 100mA·g^-1 were 107.1,103.2,and 109.6 mAh·g^-1,respectively.After three hours of reaction,the electrode contains moreβ-PbO₂ and the smallest average particle size,which shows the best electrochemical performance.The maximum discharge capacity is as high as 124.3 mAh·g^-1.After 50 cycles,the discharge capacity is reduced to 110 mAh·g^-1,but it is still 38%higher than the factory-ground ball-milled powder electrode.（2）Using the binder to replace fibers that usually used in the traditional paste,and then the positive electrode plates prepared by using the active material 4BS,the conductive agent,and the binder in different ratios were subjected to the discharge discharge performance test.When the 4BS,graphite,and PVDF materials were prepared with a mass ratio of 96.5:2.5:1,the initial discharge capacity of the corresponding battery was only 66 mAh·g^-1 and the cycle performance was poor.After the electrode was cured,the charge and discharge performance was tested.It was found that the maximum discharge capacity of the battery was 73.5 mAh·g^-1,and the capacity remained stable at 73.5 mAh·g^-1 after 100 cycles,and the cycle performance was very stable.However,the discharge capacity is slightly lower than the discharge capacity(79.5 mAh·g^-1)of the factory ball-milled lead powder as a positive electrode material.（3）PbO,PbSO₄,PVDF,and graphite are mass-proportioned to 96.5(PbO+PbSO₄(N_PbO:N_PbSO4=4:1)):2.5（graphite）:1（PVDF）as the raw material of the electrode to react in situ on the electrode to obtain the 4BS positive electrode to further enhance the internal bonding of the electrode.The electrode with a reaction time of 6 h have the smallest average particle size after chemical conversion and have the best electrochemical performance.The maximum discharge capacity is 118.9 mAh·g^-1.After 50 cycles,it can maintain about 112 mAh·g^-1.The capacity retention rate is 94%,and it is 40.9%higher than that of the factory-ground ball-milled lead powder electrode.