Multi-nanocomponent-assembled films with exceptional capacitance performance and electromagnetic interference shielding

Abstract

Fully transferring or releasing the individual characteristics associated with each involved component at different levels or scales, plays a vital role in generating synergetic or even amplified effects, which is extremely desirable for the development of a high-performance composite. However, it is still a big challenge to alleviate or even remove the negative correlation between some properties/functions with structures in a complex system, for example, both the abundant interfacial structures and the high electrical conductivity required for electromagnetic interference (EMI) shielding. In this work, we establish a concise and efficient stepwise fabrication strategy initiated from the assembly of single-walled carbon nanotubes (SWCNTs) with cellulose nanofibers (CNFs) via van der Waals interactions, resulting in the formation of amphiphilic composites, which are further assembled with reduced graphene oxide (RGO) mainly through π–π interactions, arising from the aromatic skeletons of the SWCNTs and RGO. A series of films assembled from three-nanocomponents, with different thicknesses of up to 125 μm are successfully prepared by a simple vacuum-assisted filtration without extra chemical/thermal treatments, exhibiting highly compact and consecutive layered structures. These porous films possess large surface areas (up to 106.2 m² g⁻¹) with abundant interfacial structures, high electrical conductivity up to 222.2 S cm⁻¹, as well as good mechanical flexibility and intensity. Their abundant interfacial structures and retained outstanding electrical conductivity at more than 100 μm thickness allow such types of films to deliver excellent capacitance behaviors with a high gravimetric energy density of 72.2 W h kg⁻¹, and exceptional total EMI shielding effectiveness (EMI SE_T) up to 75 dB, among the highest values of the reported carbon-based materials.