Enhanced proton conductivity and mechanical stability of crosslinked sodium alginate as a biopolymer electrolyte membrane in fuel cell application

Nafion is a commercial polymer membrane that is commonly used in fuel cell systems, despite its major limitations such as high fuel crossover and high manufacture cost. The production of sodium alginate (SA) blended membrane with crosslinking agent (glutaraldehyde) and plasticizer (glycerol) is one of several current efforts to discover an alternative membrane with improved proton conductivity and mechanical properties. In this study, SA biomembranes were prepared using solution casting method and dried at a certain temperature. Then, the prepared membranes were immersed with 5% glycerol in different concentrations of glutaraldehyde. The cross-linked biomembranes underwent various tests such as liquid uptake, swelling ratio, ion exchange capacity, proton conductivity and mechanical stability. The best membrane achieved the highest proton conductivity with a value of 8.28 mS cm-1 and mechanical stability with a value of 218.00 MPa. Glutaraldehyde made a positive modification and had a beneficial impact on the characteristics of SA. The incorporation of glutaraldehyde and glycerol within the biopolymer notably improved the otherwise lacking mechanical properties of SA.