Lightweight Ni/CNT decorated melamine sponge with sensitive strain sensing performance for ultrahigh electromagnetic absorption in both GHz and THz bands

Lightweight electromagnetic wave absorbers with high absorption performance are urgently indispensable in the application of 5G electronic devices and promising 6G communication. Herein, cost-effective approaches of autocatalytic plating and dip-coating with a series of surface grafting are proposed to construct nickel/carbon nanotube (Ni/CNT) decorated Melamine sponge (MS) composite. The resultant MS-Ni/CNT samples exhibit favorable average Reflection loss (RL) of - 25.7 dB (2-18 GHz) and - 69.7 dB (0.1-2.2 THz) at a thickness of 2 mm, respectively. Simultaneously, the Specific shielding effectiveness (SSE) value is over 45.6 dB cm3 g-1 (2-18 GHz) and 66.3 dB cm3 g-1 (0.1-2.2 THz), surpassing most reported electromagnetic wave absorbers. Particularly, to explore the transmission of electromagnetic waves, the RL values and electric field were calculated through Finite difference time domain (FDTD) simulation, and verified by experimental results. In addition, the foldable and electric properties endow the MS-Ni/CNT composite with smart pressure sensitivity which is promising for strain monitoring. The optimized MS-Ni/CNT sensor exhibits high sensitivity under a relatively small strain (4-28%). And the outstanding long-term stability and durability were also conducted by 1200 stretching-releasing cycles between 0 and 28% strain. The as-prepared electromagnetic absorber with high pressure sensing performance demonstrates enormous potential in future military and civilian applications.

Automated summary

The study proposed cost-effective approaches to construct lightweight electromagnetic wave absorbers with high absorption performance, showing superior performance in terms of reflection loss and specific shielding effectiveness. The electromagnetic absorber also demonstrated promising pressure sensing capability and outstanding long-term stability.