Cork is an expensive material for a ceiling and would require a substrate to be applied first to which the cork can be adhered.
- If there is a presence of moisture, cork being of a natural material will absorb the moisture.
- I would look into using a mold resistant gypsum board.
Gypsum is cost effective and allows you to apply color to it which could brighten up a basement (depending on the quantity of windows).
For more information:
Read "Can a cork floor in the basement hold up if there would be excess water?" a Q&A answered by Joel Hirshberg.