Graphene Improved Lead Acid Battery

Technological demands in HEVs, large scale storage and portable power stations has furthered more research interests in Lead Acid Batteries (LAB), in addition to the advantage of power rating per cost. The LAB positive active materials (PAM), due to low utilization and life cycle, severely limits the competitiveness of the traditional battery. 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. PAM-GO had the best performance with the highest utilization of 41.8%, followed by CCG-PAM (37.7%), control-PAM (29.7%), and GX-PAM (28.7%) at 2.5C rate. CCG-PAM had better charging performance such as lower internal resistance, but poorer cycle life compared to GO-PAM. Cycled at 2.5C rate, all samples but the control, had increasing capacity till after ~50 cycles. Electrochemical interaction of the graphene sheets which changed the of PbO2 crystals in the gel zone. Ion transfer model was developed showing the optimization of gel zone ion transfer induced by the electrochemical activity of graphene additives.