Influence of CuSO 4  Concentration on the Microstructure and Electromagnetic Interference Shielding Performance of Cu/EG Composites

Abstract

With the rapid advancement of electronic information technology, electromagnetic interference (EMI) has become increasingly prominent, posing potential threats to human health and the stable operation of electronic systems. Therefore, the development of high-performance EMI shielding materials has become essential for addressing this issue. In this study, expanded graphite (EG) was used as the matrix material and nanoscale copper particles were deposited onto EG layers via an electroless copper plating process, followed by hot treatment to successfully fabricate Cu/EG composites. By varying the concentration of CuSO4 in the electroless plating solution, the loading amount and spatial distribution of nanoCu particles on EG layers were controlled. This approach enabled uniform loading of nanoscale Cu particles onto EG layers and facilitated the construction of an efficient three-dimensional electron transport network, thereby significantly enhancing the overall electrical conductivity and EMI shielding performance of the composites. The results indicate that when the CuSO4 concentration was set at 1 g/L, the electrical conductivity of the fabricated Cu/EG composite reached 5.05 × 10⁴ S/m. In the X-band frequency range (8.2-12.4 GHz), a sample with a thickness of 1 mm (denoted as EG 1.0) exhibited an average shielding effectiveness of 87.3 dB. These findings demonstrate that Cu/EG composites exhibit excellent electrical conductivity and EMI shielding capabilities, highlighting their potential for application in electromagnetic interference protection for microelectronic devices.

Keywords: Electroless plating, Cu, EG, Electromagnetic shielding