This sucks. You can’t bring a battery through security (as carry-on luggage) unless it’s powering a device. So that eliminates replacement batteries for a device you aren’t carrying with you. And you can’t take a lithium battery as checked luggage in passenger aircraft. Period.
Nor does there appear to be any way (for a consumer) to ship stuff here on a genuine cargo plane.
Exactly two things have made airplane travel safer since 9/11: reinforcing the cockpit door, and convincing passengers they need to fight back. Everything else has been a waste of money. Add screening of checked bags and airport workers and we’re done. Take all the rest of the money and spend it on investigation and intelligence.