Inhibition of hydrogen evolution and corrosion protection of negative electrode of lead-acid battery by natural polysaccharide composite: Experimental and surface analysis

The investigated research illustrates the synthesis of composite polymer (GG-VA) using natural polysaccharide (Guar Gum/GG) and vinyl acetate (VA) and screening their inhibitive performance for the hydrogen gas evolution and corrosion inhibition of lead-acid battery negative electrode, i.e., Pb in 5.0 M H₂SO₄. The developed inhibitor is an environmentally friendly biological molecule and has been used for lead acid batteries for the first time as an additive. The methodology used to evaluate GG-VA inhibitive performance included hydrogen evolution and electrochemical methods, i.e., EIS and PDP. The corrosion inhibition performance of GG-VA is 88.57 %. The Pb surface was screened for GG-VA adsorption via SEM and AFM. The experimental data confirmed the reduction in hydrogen gas evolution with the addition of GG-VA. The EIS result supports the increasing R_ct values with the rising GG-VA amount corresponding to the GG-VA adsorption. PDP data reveals the mixed inhibition action and reduction in i_corr values with the addition of GG-VA. The increasing temperature causes a decrease in GG-VA performance. GG-V adsorption over the Pb surface was best described by Langmuir isotherm. The E_a data reveals the increase in the energy barrier for corrosion reaction and H₂ gas evolution in the presence of GG-VA. The SEM and AFM support the adsorbed layer of GG-VA formation at the Pb surface.