Effect of Na 2SO 4 additive in positive electrodes on the performance of sealed lead-acid cells for electric scooter applications

Abstract

This study investigated the effects of Na 2SO 4 additive in the positive electrode on the performance of sealed lead-acid cells. The additive Na 2SO 4 in the cured plates can reduce the 4BS crystal size, which produces a smaller α-PbO 2 and β-PbO 2 crystal size in the formed plates, which will have a larger surface area. The plate's chemical composition is independent of the amount of Na 2SO 4 additive in the positive electrodes. Plate composition relies only on the cure temperature conditions. Increasing amounts of Na 2SO 4 additive to the positive electrode will not decrease the crystal size appreciably. The optimal amount of Na 2SO 4 additive is 0.01–0.05 M, which produces the smallest crystal size and largest specific surface area. Cells with Na 2SO 4 additive in the positive plates have a smaller surface area, causing a higher initial capacity and average capacity per cycle for both testing methods: the standard cycle testing and the electric scooter (ES) driving pattern cycle testing. The initial capacity and average capacity can be increased up to 4% in the standard cycle testing and up to 8% in the ES driving pattern cycle testing.