Improving electromagnetic wave absorption property of metal borides/carbon nanocomposites by magnetic-electric balance and ion substitution tuning strategy

Abstract

Metal borides (e.g., MCoB) are widely used in the field of electrocatalysis due to their excellent electrochemical performance, but the poor dielectric loss limits their application in electromagnetic wave absorption (EMA). Thus, to improve the dielectric loss ability of metal borides, it needs to be compounded with dielectric materials. In this work, through reduction process and lyophilization process, Boride/PVP (MCoB/PVP) composites are obtained. After pyrolyzing these samples, Boride/Carbon (MCoB/C) nanocomposites are successfully synthesized. The EMA performance of nanocomposites are fine-tuned by balancing the magnetic and electric components and substituting metal elements of MCoB/C-X (M = Fe, Ni, Cu, X = 1, 2, 3). Among them, NiCoB/C-2 has the minimum reflection loss of −45.34 dB at thickness of 3.1 mm, and CuCoB/C-2 achieves an effective absorption bandwidth up to 6.92 GHz at thickness of 2.0 mm. This work proves the applicability of magnetic-electric balance and ion substitution tuning strategy. It also presents a new way for the application of metal borides in the field of EMA.