Improving the structural and electrochemical properties of the passive active material in graphene-enhanced lead-acid accumulators

Abstract

The aim of this study is to investigate the effect of adding graphene with different concentrations ranging from (0.05-0.2) % by weight to the negative active material in lead-acid batteries, and conducted a series of electrochemical tests to evaluate the performance, including measuring the discharge capacity, electrical efficiency, and internal resistance, during 24 cycles of charging and discharging. Also, the X-ray diffraction pattern analysis of LAB2 sample containing 0.1%

Graphene before loading process (D2) and after 24 cycles of loading and unloading. (D8).

The results showed a significant improvement in the overall performance of graphene-supported deposits, as the purity of the sample containing 0.15% of graphene (LAB3) performed best. The record of this sample is the high discharge capacity, and stability in the voltage during the high operation containers, in addition to the minimum internal resistance of 29mΩ over the cycles. Also, the graphene sample with a concentration of 0.2% achieved the highest energy efficiency of 86.98% compared to the efficiency recorded in the reference sample (LAB0) which exceeded 74.82%. And the X-ray results showed that Pbo reacts with H2SO4 during discharge and the formation of PbSO4 crystals during charging to mineral lead, and the results of the structural study show that the average crystal size of sample D8 is 33.51 nm, which indicates a relative stability in the volume of crystals compared to sample D2, where the average crystal size is 33.95 nm.

These results support the hypothesis that graphene is a promising material to enhance the electrochemical and structural properties of lead-acid batteries.