• Increased utilization of lead oxide core and increased electrode structural integrity. Abstract Graphene nano-sheets such as graphene oxide, chemically converted graphene and pristine graphene improve the capacity utilization of the positive active material of the lead acid battery.
This study focuses on the understanding of graphene enhancements within the interphase of the lead-acid battery positive electrode. GO-PAM had the best performance with the highest utilization of 41.8%, followed by CCG-PAM (37.7%) at the 0.2C rate. GO & CCG optimized samples had better discharge capacity and cyclic performance.
The Fig. 6 is a model used to explain the ion transfer optimization mechanisms in graphene optimized lead acid battery. Graphene additives increased the electro-active surface area, and the generation of −OH radicals, and as such, the rate of −OH transfer, which is in equilibrium with the transfer of cations, determined current efficiency.
The combination of cathode materials with tailored graphene based additives: Graphene Oxide (GO-PAM), chemically converted graphene (CCG-PAM) and pristine graphene (GX-PAM) resulted in improved discharge capacity and cycle life.
The plethora of OH bonds on the graphene oxide sheets at hydroxyl, carboxyl sites and bond-opening on epoxide facilitate conduction of lead ligands, sulphites, and other ions through chemical substitution and replacements of the −OH. Eqs. (5) and (6) showed the reaction of lead-acid battery with and without the graphene additives.
At 0.2C, graphene oxide in positive active material produces the best capacity (41% increase over the control), and improves the high-rate performance due to higher reactivity at the graphene/active material interface.