Sustainable Lightweight Biochar-Based Composites with Electromagnetic Shielding Properties

Area of Science:

• Materials Science
• Environmental Science
• Chemistry

Background:

• Global warming necessitates novel carbon capture materials.
• Biochar, a biomass pyrolysis product, acts as a carbon sink, primarily for agriculture.
• Understanding biochar's electrical properties is key to expanding its applications.

Purpose of the Study:

• To investigate the electrical conductivity of biochar from diverse feedstocks.
• To examine the properties of gypsum-biochar composites.
• To assess the electromagnetic interference (EMI) shielding capabilities of these composites.

Main Methods:

• Utilized various biomass feedstocks for biochar production.
• Formulated gypsum-biochar composites with varying biochar concentrations.
• Fabricated drywall-like prototypes for EMI shielding evaluation.
• Analyzed material properties including density, flexural moduli, and shielding efficiency.

Main Results:

• Gypsum-biochar composites showed reduced density and flexural moduli with increased biochar content (>20% w/w).
• Prototypes demonstrated enhanced microwave-range EMI shielding correlated with biochar concentration.
• Shielding mechanisms involved intrinsic carbon ultrastructure alignment and electrical phenomena.

Conclusions:

• Biochar's electrical conductivity and EMI shielding properties are feedstock-dependent.
• Gypsum-biochar composites offer a sustainable, lightweight alternative for EMI shielding applications.
• These materials support the development of a future bio-based economy.