My background is not chemistry and I'm new to the forum too, sorry if I'm not clear enough.
I'm looking for a simple bistable and reversible electrochemical reaction that changes color.
1) liquid in a glass with two electrodes that when applied a voltage between them, the liquid changes color.
2) When the power is removed, the new color remains (at least for a few minutes/hours).
3) When a negative voltage is applied, the liquid color changes to the original color and remains when power is removed.
4) It's possible to repeat this process many times.
It would be ideal if the chemical components were easy to get and non toxic (if possible).
The colors don't matter at all (transparent to red, blue to green, orange to white, anything really).
I hope the question makes sense!
Thanks a lot!