For example, in 2007, US researchers built tiny wind engines that created a "breeze" made up of charged particles, or ions, to cool computer chips.

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This molecular mouthful has the rare ability among solvents of being able both to dissolve cellulose and to act as an electrolyte that is, a chemical that can carry current between the electrodes of a battery in the form of charged molecules, or ions.

ECONOMIST: Storing electricity

So it is funding research into getting microorganisms to extract energy from things like metal ions abundant in the earth or solar electricity.

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This is able to happen because the space between the electrodes is filled with a material called an electrolyte which allows ions (electrically charged atoms, or groups of atoms) to pass from one electrode to the other and thus combine with their chemical complements.

ECONOMIST: Electricity storage

Plasmas are gases in which the molecules have been stripped of some or all of their electrons, to create positive ions.

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To create the metal rubber, layers of non-conducting polymers are alternated with layers of metal ions, such as gold, silver or platinum.

ECONOMIST: MONITOR

When illuminated, these "opsin" proteins change the flow of electrically charged ions within the cell, to help the cell turn light into energy or as a sensory cue.

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In the right circumstances these channels will allow the passage of sodium ions (the liquid to be investigated must have these added in the form of sodium chloride, or common salt, if they are not present naturally).

ECONOMIST: Medical diagnostics