Li-ion is almost the same as lipo but in a metel case like a standard AA cell (a little bigger) metel case makes it less likely to have damage in a crash and burning up your plane. Also I've not heard of the charging fires, like with lipo's (someone please correct me if I'm wrong here). While not recommended I don't mind charging li-ion in the plane.


I think the Fromeco.org site has some good info on Li-ion.