You joke, but, alas, there is a _real_ company kinda trying to do this. Reflect Orbital[1] wants to set up space mirrors, so you can have daytime at night for your solar panels! (Various issues, like around light pollution and the fact that looking up at the proposed satellites with binoculars could cause eye damage... don't seem to be on their roadmap.) This is one idea that's going to age badly whether or not they actually launch anything, I suspect.

Battery tech is too boring, but seems more likely to manage long-term effectiveness.

[1] https://www.reflectorbital.com

Reflecting sunlight from orbit is an idea that had been talked about for a couple of decades even before Znamya-2[1] launched in 1992. The materials science needed to unfurl large surfaces in space seems to be very difficult, whether mirrors or sails.

[1] https://en.wikipedia.org/wiki/Znamya_(satellite)