Operation of liquid e-fuel cells using air as oxidant

The promising features and capabilities of liquid fuel cells for power generation and further application in electric vehicles have drawn more research attention in recent times. Notably is the recently proposed and demonstrated fuel cell which employs an electrically rechargeable liquid fuel (e-fuel) along with a catalyst-free material at its anode. The smooth and successful functioning of the e-fuel cell generally requires the supply of oxidant at its cathode. However, the space and storage requirement with the use of pure oxygen as oxidant not only limits the energy density of the fuel cell, but as well results in higher cost. Herein, the operation and performance of this e-fuel cell is examined with the use of air as oxidant, in lieu of the commonly used pure oxygen, at the cell cathode. A peak power density of 168.3 mW cm⁻² was obtained when the cathode is fed with air. Such performance when air is employed as oxidant in the e-fuel cell outperforms most conventional direct liquid fuel cells that are even fed with oxygen and thereby demonstrates the use of air as a promising alternative for future application. The performance of the cell when operated with air at various flow rates and operating temperatures, and during a constant current discharge test were also examined. This study therefore provides basis and useful insights for future investigations towards utilizing and catalyzing air as oxidant in the e-fuel cell for improved cell performance.