Key Takeaways & Executive Findings
- •• Biomass-derived carbon (BC) materials are emerging as eco-friendly and efficient candidates for EMI shielding and EM wave absorption due to their high porosity, large surface area, and oxygen functionalities. • The review outlines synthesis strategies for BC materials and discusses mechanisms of EM wave interference, highlighting strategies to enhance dielectric loss and impedance matching. • BC composites with metal oxides, sulfides, or conductive polymers show significantly improved EMI shielding effectiveness and absorption performance. • Challenges such as scalability, uniformity, and performance optimization remain, but future prospects point toward multifunctional and tunable BC-based absorbers.
Abstract
The rising concern over electromagnetic (EM) pollution is responsible for the rapid progress in EM interference (EMI) shielding and EM wave absorption in the last few years, and carbon materials with a large surface area and high porosity have been investigated. Compared to other carbon materials, biomass-derived carbon (BC) are considered efficient and eco-friendly materials for this purpose. We summarize the recent advances in BC materials for both EMI shielding and EM wave absorption. After a brief overview of the synthesis strategies of BC materials and a precise outline of EM wave interference, strategies for improving their EMI shielding and EM wave absorption are discussed. Finally, the existing challenges and the future prospects for such materials are briefly summarized.
1. Introduction
Rapid processes in science and technology have pushed researchers to expand the microwave (MW) and magnetic techniques. However, with such technological expansion, electromagnetic pollution or electromagnetic interference (EMI) has also increased. Such specific EM pollution has significant adverse effects on human health. In order to overcome such issues, numerous EMI shielding materials as well as MW absorbing materials have been synthesized within the last few years. In general, the EMI shielding materials protect various objects mainly electronic devices by reflecting or absorbing the EM radiation[1–3]. The protective ability of such materials is measured through the EMI shielding effectiveness (EMI SE).
The ideal EMI shielding material should possess special characteristics like high electrical conductivity, low density, enhanced thermal stability, high porosity, good absorption ability, etc. In the last few years, metals, polymers, alloys, ceramics, carbon materials, MXenes, and composites have primarily been investigated for EMI shielding and EM wave absorption applications[4–23]. Among them, the carbon materials have garnered significant research interest among researchers working on EMI shielding, because of their enhanced conductivity, low density, high porosity, layered structure, high solution processability, and high surface area. The carbon materials with various dimensionalities like 0D (carbon quantum dots, graphene quantum dots, etc.), 1D (carbon nanotubes, carbon nanofibers, etc.), 2D (graphene and related derivatives), etc. have been adequately investigated as superior EMI shielding and EM wave absorption materials[5,24–26]. Besides that, the recently invented special class of materials, MXenes also demonstrated considerable EMI SE. To be suitable EMI shielding materials, carbon materials should exhibit some key physical characteristics like high crystallinity and high dispersibility in various matrices, mainly different polymer matrices. Moreover, the combination of such carbon materials with other potential materials like metal oxide/sulfide, conductive polymers, etc. further improves the shielding performance.
Apart from the pioneer carbon materials, biomass-derived carbon materials (BCs) have also been extensively investigated for various applications including supercapacitors, batteries, environmental applications, etc.[27–35]. Furthermore, the enhanced porosity, the presence of oxygen functionalities, and the existence of multiple interfaces are also the key properties of such carbon materials that make them suitable for applications in EMI shielding and EM wave absorption. Notably, such BCs display controllable MW absorption characteristics. Several strategies have also been implemented for optimizing the shielding performance of such materials. In this aspect, Fig. 1 represents the annual publication list according to the Web of Science for 2015-2024 (up to August 2024) (searched with the keyword “electromagnetic shielding and carbon and biomass”). Looking into significant research progress on this topic, a timely update on the ongoing investigations of such materials in the field of EMI shielding is highly necessary.
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Sumanta Sahoo, Rajesh Kumar, Sung Soo Han (2025). Low-value biomass-derived carbon composites for electromagnetic wave absorption and shielding: A review. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2025-2-2)
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Frequently Asked Questions
What are biomass-derived carbon (BC) materials?
Biomass-derived carbon materials are carbonaceous materials obtained from natural biomass sources such as plants, agricultural waste, or animal by-products. They are eco-friendly, porous, and often have oxygen functionalities, making them suitable for various applications including electromagnetic interference shielding and microwave absorption.
Why are BC materials considered efficient for EMI shielding?
BC materials possess high porosity, large surface area, and good electrical conductivity, which are key for EMI shielding. Their porous structure enhances multiple reflections and absorption of electromagnetic waves, while their eco-friendly nature makes them a sustainable alternative to traditional carbon materials.
What strategies are used to improve the EMI shielding performance of BC composites?
Strategies include combining BC with metal oxides, sulfides, or conductive polymers to enhance dielectric loss and impedance matching. Additionally, optimizing the carbonization temperature, activation process, and the formation of hierarchical structures can improve shielding effectiveness.
What are the main challenges in using BC materials for EMI shielding?
Challenges include achieving uniform properties, scalability of production, and precise control over pore structure and conductivity. Additionally, balancing absorption and reflection to minimize secondary EM pollution remains a challenge.
What are the future prospects for BC-based EMI shielding materials?
Future prospects include developing multifunctional materials with tunable absorption properties, integrating BC with emerging materials like MXenes, and exploring sustainable and cost-effective synthesis routes for large-scale applications.
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