Análise da resistência e do desempenho de membranas de troca protônica (PEM) à base de quitosana sob variação de temperatura

Abstract

This work investigates the fabrication and performance of chitosan-based membranes for hydrogen PEM fuel cells. The search for renewable energy sources has been increasing steadily in recent times, with a growing interest in hydrogen-based energy generation mechanisms, among which the so-called PEM (Polymer Electrolyte Membrane) fuel cells stand out. These cells, through a polymeric membrane, allow the migration of hydrogen protons from the anode to the cathode, where they combine with oxygen, generating energy and water as products. Various materials can be used for the fabrication of this membrane; in this study, the focus was placed on developing an organic membrane based on chitosan, doped with different reagents. Performance and resistance tests were conducted under increasing temperatures to evaluate the viability of this low-cost organic compound for the market. The methodology involved dissolving chitosan and polyvinyl alcohol (PVA) mixtures in a solution of sulfosuccinic acid (SSA) and hydrochloric acid, followed by drying and treatment with sulfuric acid. The resulting membranes were then used in a fuel cell for testing. The test results showed that the doped membranes exhibited good structural stability and efficient energy generation at room temperature, with voltages comparable to commercial materials such as Nafion®. During the temperature tests, distinct behaviors were observed between the membranes with and without additional sulfuric acid doping, suggesting improved thermal stability in the presence of H₂SO₄. However, overall performance remained relatively low, with functionality maintained only up to approximately 150 °C, although with potential for improvement through better system humidification. The characteristics observed suggest that chitosan membranes can be viable and sustainable alternatives for hydrogen fuel cells and may achieve even better results with further additives and modifications to enhance their thermal resistance and proton conductivity. This could contribute significantly to the energy transition using organic and renewable materials.