The shortcomings of lead-acid batteries are: low energy density and short cycle life. Lead sulfate formed by the negative plate of the lead-acid battery during the discharge process, after the battery is placed, the small particles of lead sulfate will be converted into large particles of lead sulfate, and the large particles of lead sulfate will not be converted into lead during the charging process due to the small solubility, that is, the negative plate of the battery has irreversibility during the charging and discharging process, which is called the sulfate phenomenon, resulting in the deterioration of battery performance and eventual failure. At present, by adding a certain amount of carbon material with high specific capacitance (mainly activated carbon, graphite, carbon black, etc., usually less than 2wt %) to the negative plate of the lead-acid battery to alleviate the problem, because the carbon material forms a conductive network between the active material of the plate, increasing the conductive performance of the plate, the added carbon material can store or release a large amount of charge in an instant, and the carbon material can be used to reduce the negative electrode. It plays a certain role in buffering the current of the negative plate, and can effectively inhibit the sulfation of the negative electrode and improve the cycle life of the battery under high rate partially charged state (HRPSoC). However, the hydrogen evolution overpotential of the negative electrode will decrease when carbon material is added. At present, the main addition method is to mechanically mix with micron lead powder, etc., because the density of micron lead powder is much greater than the density of carbon materials, the mixing of the two will be difficult to achieve uniformity, resulting in the lamination of the plate during the use of the battery. These undesirable phenomena can cause battery failure.

Technical features:

A kind of lead/reduced graphene oxide nanocomposite was prepared and added to the negative plate as an additive. The components were evenly distributed and well dispersed. Inhibit the appearance of large particles of lead sulfate, improve the utilization rate of active substances and the cycle life of the battery under HRPSoC.

This lead/reduced graphene oxide nanocomposite is prepared by:

Pb(CH3COO)2·3H2O, vitamin C, polyvinylpyrrolidone, graphene oxide solution and water were uniformly mixed to obtain the reaction material, which was then subjected to hydrothermal reaction, solid-liquid separation, washing and vacuum drying. The lead/reduced graphene oxide nanocomposites are obtained by pyrolysis in a nitrogen atmosphere.

Test data:

The cathodic polarization curve of Pb- rGO in the electrolyte prepared by an electrochemical test system is studied. The results are shown in Figure 1. Compared with the blank negative plate (without rGO and Pb- rGO), the current density of hydrogen evolution reaction increases with the increase of Pb- rGO added. Moreover, for the same amount of addition, the addition of rGO causes the highest current density of hydrogen evolution reaction, which proves that the prepared PbrGO has higher hydrogen evolution overpotential than the corresponding rGO, which effectively prevents the side reaction of hydrogen evolution on the negative plate of the battery during charging, and improves the cycle life of the battery.



The negative electrode performance test results show (FIG. 2) that the negative plate of Pb- rGO prepared by adding 1.0wt % has the largest specific capacity and the longest life under HRPSoC.