Parameters effect on proton conductivity to obtain chitosan membranes for use as electrolytes in PEMFC

• Published in: International journal of energy research Vol. 42; no. 3; pp. 1381 - 1385
• Main Authors: Schaffer, Jéssica V., Lupatini, Karine N., Machado, Bruna, Silva, Eliane S., Ferracin, Ricardo J., Alves, Helton J.
• Format: Journal Article
• Language: English
• Published: Bognor Regis Hindawi Limited 10.03.2018
• Subjects: Addition polymerization; Biopolymers; Chitosan; Conduction; Conductivity; Deacetylation; Evaluation; fuel cells; Fuel technology; hydrogen; Membranes; polymeric membrane; Polymers; Proton conduction; proton conductivity; Proton exchange membrane fuel cells; Protons; Thermal stability
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.3933

Summary The chitosan biopolymer can be used as a proton‐conducting membrane in proton‐exchange membrane fuel cell. In the forms that they have normally obtained and tested, chitosan membranes typically show poor performance in conduction of protons, requiring modifications in the structure of the biopolymer or blending with other polymers to increase its proton conductivity. The present work investigates the individual properties of chitosan and relates them to the proton conductivity performance of membranes composed of this polymer. Evaluation was made of the effects of variables such as the degree of deacetylation (DD) and the molar mass (Mv) of chitosan membranes without addition of any other polymer. The DD and Mv values of the chitosan used to produce membranes determined the proton conduction, with lower DD and higher Mv resulting in higher conductivity. The thicker membranes presented greater crystallinity, with conductivity between 2.0 × 10−4 and 1.8 × 10−3 S cm−1. The characteristic stages of degradation of the chitosan membranes were in the ranges 200 to 300°C and 500 to 600°C, indicating good thermal stability of the material. Lower DD and higher Mv result in higher conductivity. The membranes with higher crystallinity have higher resistance and smaller ΔM and σ. The manipulation of the properties of the pure chitosan and the characteristics of the prepared membranes can improve the performance of the material.