Consider a portable 20 cm² active area fuel cell operating steadily at 0.75V and 0.6 A/cm²

The fuel utilization efficiency is 50%, and cathode stoichiometry is 2.3 expected to run for 3 days. The cathode operates on ambient air, and anode runs off compressed H₂.

2. Determine the volume of the H₂ fuel tank required if it is stored as a compressed gas at 200 atm (20. 26 Mpa), 298K.
4. How large would a pure oxygen container be if it was used to provide the oxidizer? Consider 200 atm (20.26 Mpa) storage pressure and 298 K average ambient temperature?

For Anode,

i. Rate of total H₂consumption in 3days =a (iA/nF)

= 2.3 x (0.6 A/cm²) x (20 cm²) x 3daysx 24h/day x 3600s/h/(2e- eq/ mole of H₂) x (96485C/eq)

= 32.25 mol H₂ consumed = 32.25mol x 2 g/mol = 64.5 g H2 (check the calculation here)

PV = m(RT/MW); V _H2 = (mR/MW) x (T/P)

= [(64.5 g) x (8.314 J/mol.K) ]/(2g/mol) x (298K/20,260,000 Pa)= 0.0039 m3

= 3.9 L

ii. Similar to i. ;c = 2.3 & MW O₂= 32g/mole

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