生物质衍生多孔碳基吸波材料的吸波机理OA北大核心

The rapid development of electromagnetic wave technology brings a unprecedented convenience,but leads to some related concerns regarding electromagnetic pollution and associated health risks.Consequently,the development of electromagnetic wave absorption materials becomes crucial for ensuring both survival and safety.Biomass porous carbons(BPCs)can be used as highly promising materials for addressing these challenges due to their unique properties,including ultra-low density,large surface area,abundance of precursors,and exceptional dielectric loss capabilities,showcasing immense potential for electromagnetic wave absorption applications.However,manipulating the absorbing properties of biomass carbon-based composite materials through changes in structure and composition is restricted,and the absorption mechanisms of BPCs materials still remain unclear,due to the absence of a comprehensive framework. In this review,the absorption mechanism of BPCs materials as absorbers is explored,including impedance matching,interface polarization,multiple reflection and scattering,conductivity of network structure,pore size control to optimize absorption performance,and unique absorption mechanism of magnetic media/biomass-derived porous carbon materials.Also,several puzzles and unsolved problems of the absorption performance are emphasized,and a further research is needed to solve these uncertainties and deepen the understanding of the electromagnetic wave absorption capacity of BPCs. In addition,this review proposes a promising theoretical method to enhance the electromagnetic absorption properties of BPCs materials,providing valuable insights and directions for future research work in this field.Despite the considerable progress made in both experimental and theoretical aspects of BPCs materials,some challenges persist.These include difficulties in synthesizing highly conductive networks,challenges in precisely controlling pore parameters,and issues related to the aggregation and oxidation of magnetic nanoparticles in magnetic BPC composites,all of which require further exploration and resolution. Summary and Prospects The rapid development of electromagnetic wave technology leads to significant conveniences and also concerns electromagnetic pollution and associated health risks.Consequently,the development of electromagnetic wave absorption materials becomes crucial for ensuring survival and safety.Biomass porous carbons(BPCs)can be used as promising materials in this regard due to their unique properties such as ultra-low density,large surface area,abundance of precursors,and excellent dielectric loss capabilities,highlighting their enormous potential for electromagnetic wave absorption applications.However,despite a significant progress in manipulating the absorbing properties of biomass carbon-based composite materials,there is a fragmented understanding of the absorption mechanisms of BPCs materials,necessitating a more comprehensive framework.This review provides a thorough examination of the absorption mechanisms of BPCs materials,encompassing impedance matching,interface polarization,multiple reflections and scattering,the conductivity of network structures,control of pore size for optimizing absorption performance,and the distinctive absorption mechanisms of magnetic media/biomass-derived porous carbon materials.Furthermore,this review gives several challenges for a further exploration.One significant challenge is related to the contribution of conductive networks to the absorption performance of BPCs materials,with some aspects such as difficulties in preparation and poor stability.The precise control of pore parameters and exploration of suitable specific surface areas for optimal interface polarization effects remain major challenges in material preparation methods.Moreover,the aggregation and oxidation of magnetic nanoparticles in magnetic BPC composites affect their absorption performance,necessitating a further research in this area.Although this review is based on theoretical summaries derived from laboratory results and does not delve into the synthesis processes of the materials,it offers a comprehensive elucidation of the absorption mechanisms of BPC-based absorbing materials.This review strives to guide future research and applications via providing insights into cost-effective and high-performance BPC-based absorption materials.Some studies need to contribute to the development of efficient and versatile absorption materials via addressing these challenges and advancing the understanding of BPCs'electromagnetic wave absorption capabilities,ultimately mitigating electromagnetic pollution and ensuring public health and safety.