Conductive Wood for High-Performance Structural Electromagnetic\nInterference Shielding

Abstract

Electric\nconductors are ubiquitously used for electromagnetic shielding,\nflexible electronics, and energy storage, with metals and carbon-based\ncompounds as traditional choices for these applications. Here, we\ndevelop a conductive wood as a new type of structural electromagnetic\ninterference (EMI) shielding material with combined load-bearing function\nvia delignification and subsequent in situ chemical vapor deposition\nof polypyrrole (PPy) inside the wood channels. The centimeter-long\nwood channels are well coated by a layer of interconnected PPy, which\nprovides a high electrical conductivity of 39 S m^–1. Our results demonstrate that 3.5 cm thick conductive wood displays\nan EMI shielding effectiveness of ∼58 dB. Moreover, the conductive\nwood inherits the advanced mechanical strength of natural wood via\nthe carbonization-free process, as the compressive and tensile strengths\nof the conductive wood are about 3- and 28.7-times higher than those\nof conventional carbonized wood materials, respectively. This study\nmay pave the way for structural EMI shielding applications using scalable,\nrenewable, and cost-effective biomaterials. Its remarkable advantages,\nincluding uniform electrical conductivity, outstanding compressive\nstrength, a controllable material thickness of up to several centimeters,\nas well as its lightweight and sustainability, ensure strong potential\nfor applications in next-generation structural materials.