Lead acid batteries operate more efficiently by increasing hydrogen evolution overpotential. Battery performance
is enhanced by adding graphitic carbon nitride (g-C3N4) and carbon black (CB). The CB-g-C3N4 composite material inhibited hydrogen gas evolution by increasing the overpotential of the reaction. The bilayer configuration
of g-C3N4 stabilized nitrogen defect sites in a planar arrangement, introducing an additional energy barrier. The
25% and 50% g-C3N4 exhibited elevated overpotential relative to pure carbon material, as elucidated by density
functional theory. The research revealed a high rate-partial state of charge (HR-PSoC) cycle life of 58,000 and
47,000 cycles for 25% g-C3N4 and 50% g-C3N4, respectively, at 50% depth of discharge. These findings present
an innovative enhancement for lead-acid batteries, specifically for Idle-Stop-Go (ISG) cars, resulting in superior
performance and durability