[petelamana (OP)]

In the classic 1956 film, The Earth versus The Flying Saucers, a reference is made to "solidified electricity."  Is such a thing even conceivable, beyond the realm of science fiction?  How about solidified plasma, for that matter?

[chris]

Someone I know, who worked in the smelting and mineral refining industry, described aluminium as solidified electricity. Despite being the most abundant metal on Earth, aluminium is hard to extract from its ore (bauxite) and requires a hefty energy input to reduce it to metallic form. This is conventionally done using electrolysis of molten alumina at very high current densities. Consequently, the embodied energy in the resulting metallic aluminium ingots is huge and amounts to solid electricity.

You could, of course, reverse the process to return the electrical energy by re-oxidising the aluminium in an energy cell. There are some energy supply system prototypes that work this way, including using an aluminium/gallium alloy that can react with water to yield hydrogen:

https://www.thenakedscientists.com/articles/science-news/al-uminating-answer-fuel-cell-problem

Here's a link to the interview with Jerry Woodall where he describes his aluminium / gallium fuel cell.

[chiralSPO]

Yes, I have also heard of aluminum referred to as "congealed electricity," but despite the name, and the significant number of available electrons per unit mass in Al,  I don't think it would actually qualify as "solidified electricity."

I'm not really sure what "solidified electricity" would even be. I have only heard the word "electricity" used when referring to a flow of electric charge (AC, DC, or whatever waveform you want, but there must be current involved). So "solidified electricity" is kind of like "a molten song," there are certainly significant poetic meaning in the phrases, but nouns like song and electricity can't be described as being in one state of matter or another.

[chris]

I'm not really sure what "solidified electricity" would even be.

To my mind, the phrase is being used metaphorically.

[syhprum]

Back in the days when Wimshurst machines and electrostatics were all the rage I think they used to melt something like pitch and induce a charge into it that it retained when it solidified.

[chiralSPO]

Back in the days when Wimshurst machines and electrostatics were all the rage I think they used to melt something like pitch and induce a charge into it that it retained when it solidified.

This sounds like a type of "electret," the electrostatic equivalent of a magnet. Essentially a macroscopic object with a large permanet dipole. see more here: https://en.wikipedia.org/wiki/Electret

[Colin2B]

I think they used to melt something like pitch and induce a charge into it that it retained when it solidified.

That might be pitchblende, uranium ore, which is ionising and would neutralise a static charge.

[evan_au]

"solidified electricity."

Minerals like quartz have a charge separation built into their crystal lattice.

Despite the crystal overall being electrically neutral, you can make some of this charge appear at the surface of the crystal by stressing the crystal: The piezoelectric effect.

This is electricity in a solid form... 
See: https://en.wikipedia.org/wiki/Piezoelectricity

However, if you think of "solid electricity" being a crystal structure made entirely of subatomic particles with the same electric charge, held together in a regular crystal, I think you will find that it is impossible in our universe, due to the strength of the electric field.
- Gravity can't hold two electrons or two protons together. The electrostatic repulsion is just too great.
- Even the Strong Nuclear force can't hold two protons together (forming a Helium nucleus, but with no neutrons). This this thought to have a lifetime of around 10^-22 seconds.
- There is no equivalent to the strong nuclear force that could hold two electrons together.
- To qualify as a crystal, you need zillions of these charge carriers held together in a regular lattice, indefinitely
See: https://en.wikipedia.org/wiki/Isotopes_of_helium#Helium-2_(diproton)

The nearest we have today is the LHC, where bunches of a 100 billion protons are held together as a gas/plasma by the confining effects of microwave cavities and superconducting magnets which focus the beam. If you removed this electromagnetic confinement, the protons would fly apart in all directions (in the frame of reference of the bunch).
See: https://en.wikipedia.org/wiki/Large_Hadron_Collider#Design