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Strontium has a very low standard electrode potential and fluorine has a very high one.

$$ E_{\ce{F2 + 2e^- -> 2F^-}} = 2.87\mathrm{V} $$ $$ E_{\ce{Sr -> Sr^+ + e^-}} = -4.10\mathrm{V} $$

In theory a strontium-fluorine battery would have a voltage of $6.97\mathrm{V}$ although there are many practical reasons such as danger and rarity of materials for such batteries not to be made.

Is a strontium-fluorine battery the theoretically highest voltage chemical battery using pure elements or is it possible to obtain a higher one?

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  • $\begingroup$ You could always change the concentrations to change the EMF. But, if fluorine and strontium are indeed at the extreme opposites, you are right. $\endgroup$ – Yunfei Ma Mar 31 '16 at 3:18
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The half-potential you've given for strontium is only for the first ionisation. The half-potential you'd actually get is -2.899V for the stable dication to give a cell potential of 5.769V. From the CRC Handbook[1], lithium has the lowest element->stable ion potential of -3.0401V, which is why it's common in batteries.

[1]: Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.

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  • $\begingroup$ Can more exotic stuff such as electrides, halides and alkalides achieve higher potentials? The only standard electrode potential I can find for one of these strange anions is for the hydride anion which is 2.23V which is still not better than flourine. $\endgroup$ – Steven Stewart-Gallus Apr 7 '16 at 0:03

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