An easy-to-fabricate, submerged Carbon-based air cathode for biofuel cells

• Main Authors: Wan Mohd Sukri, Wan Nur Asiah, Othman, Raihan, Sarifuddin, Norshahida
• Format: Article
• Language: English; English
• Published: IIUM Press 2024
• Subjects: TJ807 Renewable energy sources; TK2896 Production of electricity by direct energy conversion; TP248.13 Biotechnology
• Online Access: http://irep.iium.edu.my/113556/7/113556_An%20easy-to-fabricate%2C%20submerged.pdf; http://irep.iium.edu.my/113556/13/113577_%20AN%20EASY-TO-FABRICATE%2C%20SUBMERGED%20CARBON-BASED%20AIR%20CATHODE%20FOR%20BIOFUEL%20CELLS_SCOPUS.pdf; http://irep.iium.edu.my/113556/; https://journals.iium.edu.my/ejournal/index.php/iiumej; https://doi.org/10.31436/iiumej.v25i2.2974
• Institution: Universiti Islam Antarabangsa Malaysia

An air cathode (AC) is one of the main components in an AC-based biofuel cell (BFC). Its cost accounts for nearly half of the total cost of the cell as specific requirements must be met for it to perform as an effective site for the oxygen (O2) reduction reaction (ORR) to occur. In most applications where the AC is totally submerged in the electrolyte, air or O2 is bubbled throughout the electrolyte during the entire discharge operation to enhance the cell performance. This is because the dissolved O2 (DO) concentration is merely one-third of the O2 concentration in ambient air. Unfortunately, this approach increases the overall complexity and cost of the system. Therefore, this present study developed an effective, easy-to-fabricate AC for use under totally submerged and unaerated conditions. The design principle of the proposed AC is a balance between the hydrophobicity and hydrophilicity of the components used, i.e., the combination of a carbon felt, an interwoven carbon fiber sheet, and a nickel mesh. All the cathode components were snugly fitted merely using the mechanical pressure of the cylindrical BFC holders. The fabricated AC was assembled in a zinc-air BFC employing fungal microbes Phanerochaete chrysosporium (P. chrysosporium). When tested at a constant current of 1.0 mA under unaerated, uncontrolled ambition conditions, the zinc-air BFC discharge lasted 42 days with an average operating voltage of 200 mV. Under these conditions and even without the inclusion of any catalytic material, the cell performance met the operating requirements of the low-powered remote sensing devices. Therefore, the proposed easy-to-fabricate submerged air electrode has demonstrated its viability for use in BFCs.