PANI/CFO@CNTs ternary composite system for EMI shielding applications

•We report EMI shielding properties of composites made of carbon nanotubes decorated with cobalt ferrite nanoparticles and coated with polyaniline.•The formation of CFO, CNTs and emeraldine form of PANI was confirmed by XRD and Raman spectroscopy.•CNTs content has been varied to tune the dielectric permittivity to match it with the magnetic permeability to achieve good impedance matching.•PANI/CFO@CNTs ternary composite exhibited total shielding effectiveness of 16.80 dB corresponding to 97.90 % attenuation.•Dielectric and magnetic loss processes, enhanced impedance matching, and an entangled 3D structure are all responsible for the improved EMI shielding capabilities.