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A primary battery using metallic lithium and iron disulfide. The overall discharge conversion consumes four lithium atoms and releases four electrons per $\mathrm{Fe}{\mathrm{S}}_2$ formula unit. This is distinct from the rechargeable host-to-host transport in a conventional lithium-ion battery.

This lithium iron disulfide battery consumes a metallic lithium anode and converts iron disulfide into iron and lithium sulfide. Commercial cells of this chemistry are primary batteries. A conventional lithium-ion battery is designed for reversible cycling: lithium ions transfer between two host electrodes, commonly a carbon insertion anode and a transition-metal compound cathode, while electrons travel in the external circuit. Metallic lithium is not the intended normal anode reactant in that design. Primary Li/FeS₂ conversion is the key distinction from the rechargeable lithium-ion host-electrode system. The fact that both transport lithium ions does not make them the same battery chemistry, and a nominal 1.5 V is not a definition of either class.^[ref]

Two electrons are transferred per formula unit of Li2O2. Its theoretical specific capacity isAt $3\mathrm{V}$, the corresponding theoretical specific energy is $3q=3.50\mathrm{Wh}{\mathrm{g}}^{-1}$, or $3500\mathrm{Wh}\mathrm{k}{\mathrm{g}}^{-1}$. 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.

Yi Cui develops nanomaterials and methods for studying their structure and behavior, with applications including lithium-ion batteries, catalysis and environmental technologies. His Stanford research description identifies this combination of material design and characterization.^[ref] He also coauthored the indium tin oxide study cited here.^[ref]

A useful geometric motivation for nanoscale design is that a sphere's surface-area-to-volume ratio is $3/r$. Reducing its radius tenfold increases that ratio tenfold, changing how much material lies near an interface. In an electrode, small dimensions can also shorten transport distances, while a greater exposed surface can increase unwanted reactions. Useful material design must therefore test the complete device behavior rather than assuming smaller features improve every property.