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Electrolysis and hydrogen fuel cell

Vary current and time to compare hydrogen and oxygen amounts and round-trip energy losses.

    EN04 · Electrolysis and hydrogen fuel cell0.00 s · Ready

    Energy & Environment · Renewable energy / Principles and inquiry

    Electrolysis and hydrogen fuel cell experiment guide

    Vary current and time to compare hydrogen and oxygen amounts and round-trip energy losses.

    How does it work?

    Electrolysis produces hydrogen and oxygen in a 2:1 ratio. Reversing the reaction does not recover all electrical energy.

    Key relationship

    n(H₂) = It/(2F) · n(O₂) = It/(4F) · F = 96485.33212 C/mol

    Try this investigation

    1. Vary current and time to compare hydrogen and oxygen amounts and round-trip energy losses.
    2. Run and record each of the three reference settings.
    3. Change one variable in each comparison and compare its energy results with the baseline.

    Interpreting your results

    For equal charge, what fraction of electrolysis input returns as electricity?

    38.9 % · Electrolysis produces hydrogen and oxygen in a 2:1 ratio. Reversing the reaction does not recover all electrical energy.

    Assumptions and limitations

    The model assumes 100% Faradaic efficiency, 1.8 V electrolysis, a 0.7 V fuel cell and hydrogen HHV of 285830 J/mol. Compression, leakage and kinetics are omitted. Do not reproduce this with real gas, flames or high voltage.