Porous polyolefins are widely used as barrier against short circuits in commercial lithium ion battery separators due to their excellent electrochemical stability. However, their porous structure results in poor mechanical properties, especially when the diaphragm is subjected to external local impact. A team of the CAS University of Science and Technology of China has substituted the random structured ceramic nanoparticle layer, presently used on top of the separator, by ion‐conductive porous multilayers consisting of highly oriented aragonite platelets. This nacre‐inspired coating can sustain external impact by turning the violent localized stress into lower and more uniform stress due to the platelet sliding, as shown by good cycling stability under external shock.