Am I understanding that you want to use your iPad to charge your Kobo? that will never work.
Your iPad should have come with a USB cord to charge it with.
if you're wanting to charge your Kobo without having to use a PC, there are tons of commercial power adapters to charge via USB. Kobo probably sells one, but if you want a third party one, just look for the power specs required by your Kobo, then find a third party one that matches and you're set to go.