I'm planning to incarcerate a supervillain who has the ability to attract and control metal. As a minimum, I'd quite like to light his cell but obviously putting even small amounts of metal into his proximity (100+ metres) is extremely dangerous.
Is there a way of creating an electrical lighting circuit that doesn't use any metal whatsoever?
In my head we're using a chemical bath to generate electricity, water-filled glass tubes to conduct the electricity and some kind of non-metallic conductor to create the lighting but I'm wide open to suggestions. Acceptance will be given to a suggestion that is wholly based on real-world examples.