Eggshell membrane-based water electrolysis cells

Naturally occurring biofilms are sought after for tremendous applications. Here eggshell membranes, biofilms separated from eggshells-a bio-waste-having a thickness of ∼50 μm, are shown for their potential in alkaline and acidic water electrolysis. Chemical modification by quaternization leads to an enhanced anion exchange performance of the eggshell membrane, which is on par with a commercial anion exchange membrane (Fumasep FAS-50). Morphological studies show a dense network of interconnected porous fibers in the eggshell membrane, providing considerable mechanical strength and flexibility (stress and strain at failure ∼2 MPa and ∼60%, respectively) to the membrane. The anion (OH^-) and cation (H⁺) exchange capacities of the functionalized eggshell membranes are compared with those of the commercial membrane using chronoamperometry studies conducted with a homemade water electrolysis cell as well as with a membrane electrode assembly set-up. Studies show the potential of this low cost membrane in commercial anion and/or cation exchange membrane-based energy technologies.