Enhanced Dielectric Performance of Polymer Nanocomposites Based on CNT/MnO₂ Nanowire Hybrid Nanostructure

We report a new highly efficient polymer nanocomposite for charge storage applications based on carbon nanotube (CNT) and MnO 2 nanowire (MnO 2 NW). Our study suggested that combination of conductive filler (CNT) and ferroelectric filler (MnO 2 NW) is an effective method to fabricate nanocomposite with outstanding dielectric permittivity and low dielectric loss if two fillers share similar length and geometry. This strategy leads us to fabricate a hybrid nanocomposite (CNT:MnO 2 NW (3.0:4.5 wt %)) with a high dielectric permittivity (50.6) and low dielectric loss (0.7), which are among the best-reported values in the literature in the X-band frequency range (8.2–12.4 GHz). We postulated that superior dielectric properties of the new hybrid nanocomposites were attributed to (i) better dispersion state of CNT in the presence of MnO 2 NW, which increases the effective surface area of CNTs, as nanoelectrodes, (ii) dimensionality match between the nanofillers, which increases their synergy, and (iii) barrier role of MnO 2 NWs, cutting off the contact spots of CNTs and leading to lower dielectric loss. Comparison of the dielectric properties of the developed hybrid nanocomposites with the literature highlights their great potential for flexible capacitors.