Elemental doping and size effect-modified biomass-derived carbon: a fascinating microwave absorbing/shielding and energy saving material

Abstract

The center of polarization induced by hybrid elements and the size effect have been proven to be effective ways to enhance microwave absorption. The effects of specific surface area ratio and doping of elements (P, S, N) on microwave absorption characteristics were studied using almond shells as the raw material, and the particle size effect was evaluated using ball milling. The modified material displayed a doped conjugated porous structure and red phosphorus implanted carbon nanotubes onto the bio-based surface. Interestingly, cement was used as an absorbing substrate to make the absorbing composites, showing the fascinating electromagnetic interference shielding effectivenesses (EMI SEs) and microwave absorption properties. For example, S-BPAS with a thickness of 3.15 mm obtained a reflection loss (RL) of 99.42 dB, whereas BPAS with an ultra-low thickness of 1.20 mm obtained a wide effective bandwidth of 5.38 GHz. In particular, the total SE of BPAS and P-BPAS in the x and ku bands is ≥90%. The research results open up new prospects for the development of advanced functional materials that can save energy and purify electromagnetic pollution.