Carbon nanotube-carbon black/CaCu₃Ti₄O₁₂ ternary metacomposites with tunable negative permittivity and thermal conductivity fabricated by spark plasma sintering

Metacomposites with negative permittivity usually possess huge dielectric loss, showing potential for micro-wave attenuation devices where huge heat would generate. Herein, carbon nanotube-carbon black/CaCu₃Ti₄O₁₂ (CNT-CB/CCTO) ternary metacomposites were fabricated by spark plasma sintering. The CNT-CB dual-phase filler was pre-pared through electrostatic self-assembly process in order to construct an effective 3-dimensional (3D) carbon network in CCTO matrix. The percolation threshold of CNT-CB/CCTO composites was identified at filler content of 12.52 wt% which accompanied with an essential change of conduction mechanism. The negative permittivity was derived from low-frequency plasmonic state of the 3D carbon network, described by Drude model. The problem of heat transport, generally occurring in negative permittivity materials, has been solved and optimized in obtained ternary metacomposites benefitting from the substantially high thermal conductivity (9.49–2.00 W·m⁻¹·K⁻¹) and diffusivity (2.74–1.22 mm²·s⁻¹). This work could spark significant development of practical application of metacomposites on novel electronic devices and electromagnetic apparatus.