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I'm just curious about this topic, as most portable, "clean" energy sources or carriers (in the sense of not being a primary energy source -fuel cell hydrogen, for example) are in essence electrochemical reactors, and most of the current work in the field is aimed at reducing irreversible losses at the electrodes, be it because of discharge overpotential, or polarization because of mass transfer along the membrane electrolyte; and of course, in making this structural elements cheaper.

Also, a lot of proposed and existing waste treatment and recycling processes aimed at recovering rare and/or active metals (such as lithium from Li-ion batteries) involve at least one electrochemical unit op.

I wonder if nanotechnological advances, such as increasing the surface area of electrode materials or increasing the effecive diffusivity of relevant species in solid porous electrolytes, can reduce this irreversibilities, perhaps making use of cheaper raw materials than noble metals (i.e. platinum). I would also appreciate any references to current work in this applied field.

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  • $\begingroup$ if it can be reduced, then why not. $\endgroup$ – BigSack Aug 25 '12 at 6:54
  • $\begingroup$ I was wondering if someone here could give me a more comprehensive answer and/or references. But what you wrote is more than I could ask for :) $\endgroup$ – Mono Aug 25 '12 at 23:28
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Nanotechnology offers enormous opportunities for improving a huge range of electrochemical processes.

The use of platinum as a catalyst is been widespread throughout the electrochemical industry, helping reduce the activation energy of reactions such as in hydrogen and methanol fuel cells. However, platinum is a rare and expensive metallic element. Given that the reactions only take place on the surface of the catalyst, the use of nanoparticles of platinum reduces the amount of platinum needed to achieve the same surface area, thereby achieving the same performance at a fraction of the cost.

Another interesting application is in lowering the operating temperature in solid oxide fuel cells.

A good reference on Nanotechnology in Electrocatalysis for Energy, which covers background fundamentals and some applications, can be read on Google Books for free.

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Speaking specifically on lithium-ion batteries, it depends. Smaller cathode particles tend to allow more lithium diffusion due to reduced diffusion path length, which means better kinetics. However, smaller particles also have larger surface energies, meaning you might have to pay a high penalty in the form of overpotential.

source article

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