Cryogenic-environment resistant, highly elastic hybrid carbon foams for pressure sensing and electromagnetic interference shielding

Elastic carbon foams are promising material candidates for various applications, including strain/pressure sensing and electromagnetic interference (EMI) shielding, but typically suffer from brittleness, low sensitivity, narrow pressure detection range, and poor performance stability. Herein, a facile and scalable method was demonstrated to fabricate carbon nanotube (CNT) embedded carbonized melamine foams (CNT/CMFs) by a direct pyrolysis process. The hybrid CNT/CMFs show tunable electrical conductivity while providing ultrahigh elasticity even under deep cryogenic conditions (−196 °C). An ultrahigh sensitivity (up to 103.24 kPa−1) and a broad pressure detection range (0–175 kPa) were achieved by the hybrid foam sensors, attributing to the hierarchical structures composed of a nanofibrous CNT layer and macropores. The foam-based sensors exhibit ultrahigh cryogenic-temperature resistance, which retains stable performance after immersing in liquid nitrogen for 36 h and experiencing 5000 cycles of repeated compression-release. Moreover, the CNT/CMFs show an exceptional EMI shielding effectiveness and a high specific shielding effectiveness of 6147.3 dB cm2 g−1 with an absorption-dominant shielding mechanism due to the highly porous structure. The cryogenic-temperature resistant CNT/CMFs with these superior strain/pressure sensing and EMI shielding performance are promising for their practical applications as wearable electronics operating in both mild and harsh environments.