Quantum Batteries

December 21, 2009

I’ve written here several times about potential advances in battery technology (including sodium ion batteries, rechargeable zinc-air batteries, and nuclear batteries).   Now Technology Review has an article describing another new battery technology: digital quantum batteries,  a concept proposed by a physicist at the University of Illinois at Urbana-Champaign, Alfred Hübler.  The proposed device is actually a sort of hybrid battery/capacitor:

The concept calls for billions of nanoscale capacitors and would rely on quantum effects–the weird phenomena that occur at atomic size scales–to boost energy storage

A conventional capacitor stores energy in an electric field that is created when electric charge is applied to two parallel plates. (A conventional battery, by contrast, stores chemical energy which it converts to electricity.)  Capacitors can be charged and discharged much faster than batteries, but their storage capacity is limited; apply too much charge, and electrical arcing between the plates will occur.

In Hübler’s design, the “battery” is actually an array of a large number of nanoscale capacitors.  In theory, quantum effects that manifest themselves only at such small scales would act to reduce arcing:

If capacitors were instead built as nanoscale arrays–crucially, with electrodes spaced at about 10 nanometers (or 100 atoms) apart–quantum effects ought to suppress such arcing.

If the device can be fabricated successfully, and if the theoretical calculations of its properties prove accurate, the improvement in energy storage could be substantial:

Hübler claims the resulting power density (the speed at which energy can be stored or released) could be orders of magnitude greater, and the energy density (the amount of energy that can be stored) two to 10 times greater than possible with today’s best lithium-ion and other battery technologies.

Today, the quantum battery is only a research concept, but Hübler believes that the devices could be fabricated by existing lithographic technologies used to manufacture semiconductor chips, using metals such as iron or tungsten on a silicon substrate.  He thinks that a lab prototype might be developed in about a year.  Nanoscale capacitors have been fabricated, by researchers in Korea, but the quantum battery would require millions of them to be practical.  (The concept is discussed in more detail in a paper [PDF], of which Hübler is the lead author, to be published in the journal Complexity.)

As I’ve noted before, developing new batteries and other types of energy storage technologies are critical in allowing us to shift to greater reliance on renewable energy sources like solar or wind power.  The quantum battery is one of the moe exotic concepts that has been proposed, and it’s not clear that it will become a viable product; but this kind of research is of tremendous importance to developing a sensible energy strategy for the future.

Cooking, Revisited

December 21, 2009

I’ve written here before about Prof. Richard Wrangham’s hypothesis s that cooking, in addition to being a distinctly human trait, also played a key role in shaping human evolution.  The New Scientist now has a brief recent interview with Prof. Wrangham, a professor of anthropology at Harvard, in which he discusses some of the reasoning behind the hypothesis.   He also suggests that the advent of cooking may have to some extent influenced the development of gender roles in society, a claim that will almost certainly raise some hackles; however, as Prof. Wrangham says, to make the claim is not to argue that it should be that way now.

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