Gradient in-plane oriented porous carbon inspired by fabrication of toasts for elegant EMI shielding performance

As electromagnetic pollution becomes more and more serious nowadays, efficient electromagnetic interference (EMI) shielding materials with lightweight, elegant mechanical behavior, and designable structure become desperately needed. Multiple reflections in materials can improve the EMI shielding efficiency effectively, which is a priority when designing EMI shielding materials. Inspired by the fabrication of toasts, the dough can be stretched into extremely thin sheets, and the large-scale deformation makes the micro components in-plane arranged in the porous carbon. The obtained porous carbon exhibits an anisotropic EMI shielding performance with a ratio of 1.45:1 (vertical to the sheets: parallel to the sheets) due to the multiple reflections between the oriented layers. Furthermore, water for kneading is replaced with graphene oxide (GO) solution, and the GO@dough is stretched into thin sheets with GO nanosheets in-plane oriented. The obtained porous carbon exhibits the highest SET value of 33.95 dB in X band (vertical to the sheets). Additionally, by arranging the sheets with a gradient concentration of reduced GO, surface impedance matching is improved with an increased value of SEA, and the gradient porous carbon exhibits elegant EMI shielding performance over 54 dB and average absolute shielding effectiveness reaching 530 dB cm²/g throughout the X band.