= Solution
Two <electrons> are transferred per formula unit of Li2O2. Its theoretical <specific capacity> is
$$
\boxed{q=\frac{2F}{3600M}=\frac{2(96500)}{3600(46)}=1.165\,\mathrm{Ah\,g^{-1}}.}
$$
At $3\,\mathrm V$, the corresponding theoretical <specific energy> is \b[$3q=3.50\,\mathrm{Wh\,g^{-1}}$], or $3500\,\mathrm{Wh\,kg^{-1}}$. The mass basis is Li2O2, equivalently the combined stoichiometric masses of consumed Li and O2; a value normalized to Li metal alone would be different.
A real <lithium-air battery> also includes <electrolyte>, porous positive-electrode support, separator, current collectors, excess reactants, packaging and possibly oxygen treatment. Insulating Li2O2 can block pores and <electron> transport, limiting utilization; polarization, <electrolyte> decomposition, moisture/CO2 contamination and parasitic reactions lower useful <voltage> and reversible capacity. A <lithium-ion battery> instead shuttles Li <ions> between pre-existing host <electrodes>, generally in a closed cell without consuming atmospheric oxygen; the oxygen/peroxide reaction and its mass/transport requirements make the Li-air mechanism distinct.
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