Noooo not with a cellphone! I'd really stay away from your regular smartphones, if you really want to couple it to a mobile device get an encrypted phone, but for that price you can get like 10 trezors...
I paid $11 apiece for two of these, so i could get like 5 of these for the price of a trezor, I have also disabled all data capabilities including gps, you can even disable the eternal hardware, (cut the internal antenna's etc). This is no longer a phone. its a cold offline device