In situ reduction of copper nanoparticles in porous carbonized wood for efficiently enhancing electromagnetic interference shielding performance

Abstract

In this study, porous carbonized wood was used as the substrate, and a multi-layer composite of copper/carbonized wood/copper (Cu/CW/Cu) layer with light weight, flame retardancy, and efficient electromagnetic shielding effectiveness was prepared by electroless copper method. The results showed that the copper particles can be filled in the layered porous structure of the carbonized wood. The metal Cu layer was evenly covered on the surface of the whole carbonized wood, and the average surface roughness was 7.62 µm. The absorption peak at 2340 cm⁻¹ was significantly enhanced, which proved that the increase of the number of electroless Cu on the carbonized wood surface promoted the improvement of Cu autocatalytic ability. After three depositions of Cu, the conductivity of the composite material reached 1154 S/cm, showing good electrical properties. The shielding effectiveness in the X-band from 8.2 to 12.4 GHz was up to 55.97 dB at low density (0.27 g/cm³). Specific shielding effectiveness S_SE/t was as high as 581.69 dB cm² g⁻¹. Through the “absorption–reflection–absorption” path, high absorption and low reflection are achieved, shielding a large number of incident electromagnetic waves.

HIGHLIGHTS

1. The wood porous carbonization composites can be obtained via electroless Cu.

2. The wood-based composite had ideal conductivity.

3. The composite exhibited excellent EMI SE (55.97 dB) at low density (0.27 g/cm³).

4. Specific shielding effectiveness S_SE/t was as high as 581.69 dB cm² g⁻¹.

Keywords:

• Wood porous carbon
• electroless Cu
• conductivity
• electromagnetic shielding

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Additional information

Funding

This work was supported by the Central Government Guides Local Funds for Scientific and Technological Development [Grant No. 2023ZY0010], the Program for Improving the Scientific Research Ability of Youth Teachers of Inner Mongolia Agricultural University [Grant Nos. BR230113, BR230160], the Natural Science Foundation of Inner Mongolia Autonomous Region [Grant No. 2022MS03006], and the Undergraduate Innovation and Entrepreneurship Training Program [Grant Nos. 202310129009, 202310129013, 202310129014, 202310129038, 202310129068, 202210129007].