Battery electrolyte proton transport

The premise of this article is proton, hydrogen ions, are an efficient transport: Proton transport 'highway' may pave way to better high-power batteries

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Here's how it works: Electrical charge is conducted when a hydrogen atom bridging two water molecules "switches its allegiance" from one molecule to the other, Wu explains.

"The switch kicks disjointed one of the hydrogen atoms that was covalently bonded in the second molecule, triggering a chain of similar displacements throughout the hydrogen-bonding network," he said. "The motion is like a Newton's cradle: Correlated local displacements lead to the long-range transport of protons, which is very different from metal-ion conduction in liquid electrolytes, where solvated ions diffuse long distances individually in the vehicular manner."

Added Ji: "The cooperative vibrations of hydrogen bonding and hydrogen-oxygen covalent bonds virtually hand off a proton from one end of a chain of water molecules to the other end with no mass transfer inside the water chain."
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I did not realize that protons have no mass. Sorry for the snark but this was a sad mistake.

The transport of ions through the electrolyte is what makes a battery work. There is merit in using the smallest ion, hydrogen protons. However, there remains a major problem of what happens to the volume of the cathode and anode. With rare exception, there is a tendency for the electrode volumes to change and that poses a serious mechanical problem. So they state the obvious:

. . . Right now the battery community focuses on lithium, sodium, and other metal ions, but protons are probably the most intriguing charge carriers with vast unknown potentials to realize."​

There is one example, NiMH batteries that store hydrogen in the metal hydride matrix.

Bob Wilson