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We are actually not so far away from hitting the ceiling with batteries. There are fundamental physical reasons for why you can't put much more than 1eV per ato
by semi-extrinsic 12y ago
We are actually not so far away from hitting the ceiling with batteries. There are fundamental physical reasons for why you can't put much more than 1eV per atom in a battery. That equates roughly to 850 Wh/kg, if memory serves, and we are currently pushing Li-ion towards 300 Wh/kg. So we can only keep growing at 5% for another couple of decades or so. Regardless of battery chemistry.
What people often do to hide this fact is talk about energy density, Wh/L, where growth can continue for longer, at the expense of making batteries heavier.
- Filligree 12y agoGasoline manages 12kWh/kg, and I'm sure I've heard people talking about batteries at least approaching that density before, even if only on a theoretical basis. Leaving aside how safe I'd feel with a supercap of that density under the hood, are you sure about the 800Wh/kg limit? I'd be very interested in seeing a reference.
- jontro 12y agoFound this article discussing some limits http://chargedevs.com/features/three-of-a-kind-polyplus-reaches-for-1500-whkg/ http://chargedevs.com/features/three-of-a-kind-polyplus-reac...
- semi-extrinsic 12y agoThe 1eV per atom is really a rule of thumb, but easy to understand: At that value you are getting dangerously close to the ionization energy 13.6 eV for hydrogen, 5.4 eV for lithium), so you can no longer have a chemical battery. Note also that this is average eV for all atoms in the battery, so those actually providing electricity will be carrying atound 1.5 - 2 eV. See e.g. here: http://www.ohio.edu/people/piccard/radnotes/radioactive.html http://www.ohio.edu/people/piccard/radnotes/radioactive.html