Polarization and matching modulation of peapod-like Cu/C nanowires to improve microwave absorption

摘要

Unique peapod-like Cu/C core-shell nanowires (CSNWs) were specifically designed and synthesized to overcome the disadvantages of Cu NWs (i.e., low microwave absorption capability, poor chemical stability, and high density) for applications in microwave devices. Herein, Cu/C CSNWs were synthesized via a hydrothermal-sintering approach, in which the structural evolution from solid NWs to peapod-like NWs and even to hollow nanotube can expediently be achieved by changing the aging time. Such changes can effectively modulate impedance matching, dielectric loss, and conductivity. Compared with other Cu-based absorbers, the present peapod-like Cu/C CSNWs exhibited broader effective bandwidth of (6.96 GHz; RL <= -10 dB), strong absorption (- 39.43 dB) and lower filling mass fraction (15 wt%). The superior performance with broad band, light weight, and strong absorption of the CSNWs can be attributed to the enhanced impedance matching and permittivity, low filling mass fraction, high attenuation, multiple scattering, and plasmon resonance absorption. Moreover, the carbon shell significantly improved chemical stability. This work presents a new strategy to design advanced peapod-like microwave absorbers for various microwave absorption applications. (C) 2020 Elsevier B.V. All rights reserved.