Complex sentence: Because the foil is very thin, it is extremely flexible; the extreme thinness of the foil means that the maximum bend radius imposed on the foil is many times the thickness of the foil, leading to a low probability of metal fatigue.
Split into simpler sentences: Because the foil is very thin, it is extremely flexible. In addition, the extreme thinness of the foil means that the maximum bend radius imposed on the foil is many times the thickness of the foil, leading to a low probability of metal fatigue.