A New Strategy of 3D Printing Lightweight Lamellar Graphene Aerogels for Electromagnetic Interference Shielding and Piezoresistive Sensor Applications

Lamellar 3D structures are beneficial to raise the electrical properties of graphene aerogels like electrical conductivity, electromagnetic interference (EMI) shielding efficiency (SE) and pressure sensitivity. In this paper, a strategy of 3D printing lamellar graphene aerogel (LGA) based on shear-thinning and ice-growth-inhibition mechanisms is demonstrated. A well-designed slit extrusion printhead is used to produce shear thinning graphene oxide (GO) water-based dispersions. Tert-butyl alcohol is added into GO water-based dispersions to inhibit ice growth which will destroy the GO flakes arrangement. After freeze-drying and chemical reduction of the printed GO samples, the lightweight LGAs are prepared. Comparing to the traditional way, the strategy in this paper shows much better size and shape scalable freedom. The LGA exhibits electrical conductivity up to 705.6 S m(-1), which is rather high for graphene-based aerogels. Benefiting from the lamellar structure and high electrical conductivity, the aerogel achieves up to 68.75 dB EMI SE at X-band with the thickness of 3 mm, while the absolute EMI SE can reach up to 15351.9 dB cm(3) g(-1). The LGA can also be used as a piezoelectric pressure sensor, which exhibits high compressible stress and rapid response time.