A new paper in PRL has a very interesting theoretical calculation for lead-acid battery used in motor vehicles. Supposedly, there are no ab initio calculations for such battery works, i.e. no theoretical calculation for the energies of the reactants - till now[1]!

Abstract:

*The energies of the solid reactants in the lead-acid battery are calculated ab initio using two different basis sets at nonrelativistic, scalar-relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13 V, compared with the experimental value of 2.11 V. All calculations agree in that 1.7–1.8 V of this standard voltage arise from relativistic effects, mainly from PbO2 but also from PbSO4.*

But what made it stood out is the end of of the paper, where the authors wrote "

*"! :)*

**Finally, we note that cars start due to relativity**Well, there ya go! If anyone questions you on the use of relativity, you point to their car batteries!

I love it!

Zz.

Edit: Don't miss the Physical Review Focus coverage of this work.

[1] R. Ahuja et al., Phys. Rev. Lett. v.106, p.018301 (2011).

## 4 comments:

that *is* great! ha.

Glad you like it :)

Patryk Zaleski-Ejgierd

I dont understand this.how does relativity help my car start.????And what "relativistic effects" is the author referring to??

Very interesting to read this paper on Lead-acid 'batteritivity' and the other one on mercury battery.But then any heavy atom conforming to jj coupling taking part in an electron transfer event is expected to show relativistic effects such as reported here. In fact in DFT calculations in many cases dont yield agreement unless one takes relativistic effects into account.

A dramatic effect of relativity ( as I wrote in a Poster item several years ago and talked about it in 2004 in an Einstein Seminar is when one 'Bends it like Einstein" ('it' meaning electron beam and the 'bender' is a magnetic field). The case of synchrotron radiation!

Sunandana

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