Read the full article here: Adv. Mater. 2018, 1802477. Synthetic mimics of natural high‐performance structural materials have shown great and partly unforeseen opportunities for the design of multifunctional materials. For nacre‐mimetic nanocomposites, it has remained extraordinarily challenging to make ductile materials with high stretchability at high fractions of reinforcements, which is however of crucial importance for flexible barrier materials. Here, highly ductile and