Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value....Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value.In this work,the wood-derived porous carbon(WPC)skeleton from natural wood was performed as a template.And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites,based on highly ordered honeycomb cells inner WPC as a microreactor.Higher carbonization temperature is more conducive to the graphitization degree of natural wood.MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 d B at density as low as 0.197 g/cm^3.Such wall-like"mortar-brick"structures(WPC skeleton as"mortar"and MXene aerogel as"brick")not only effectively solve the unstable structure problem of MXene aerogel networks,but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy,thereby exhibiting the superior EMI shielding performance.In addition,MXene aerogel/WPC composites also exhibit good anisotropic compressive strength,excellent thermal insulation and flame retardant properties.Such ultra-light,green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry,etc.展开更多
Metal-organic frameworks are compounds with a reticulated skeletal structure formed by chemically bonding inorganic and organic units that are widely used in many fields, such as photocatalysis, gas separation and ene...Metal-organic frameworks are compounds with a reticulated skeletal structure formed by chemically bonding inorganic and organic units that are widely used in many fields, such as photocatalysis, gas separation and energy storage, because of their unique structures. In this paper, we prepared a metal-organic framework [(<em>μ</em><sub>2</sub>-2-methylimidazolyl)<sub>12</sub>-Zn(ii)<sub>6</sub>-H<sub>18</sub>O<sub>10</sub>]<sub>n</sub>(ZM) with well-developed pores and high specific surface area of MOFs by the solution method. And MOF-derived porous carbon was prepared by the direct charring method in an argon atmosphere using a mixture of ZM, ZM and potassium citrate as carbon precursors. Characterization analysis revealed that the maximum specific surface area of ZMPC-800-1:15 was 2014.97 m<sup>2</sup><span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, and the pore size structure was mainly mesoporous. At a current density of 1.0 A<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup> the specific capacitance of ZMC-800 and ZMPC-800-1:15 was 121.3 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup> and 226.6 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, respectively, with a substantial increase of 86.8%. The specific capacitance of ZMPC-800-1:15 decays to 168.8 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, with a decay rate of 25.5%, when the current density increases to 10.0 A<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>. After 5000 constant current charge/ discharge cycles, the capacitance retention rate was still 96.41%. These results prove that the application of MOF-derived carbon materials in future supercapacitors is very promising.展开更多
基金supported by the Foundation of National Natural Science Foundation of China(51973173)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+2 种基金Space Supporting Fund from China Aerospace Science and Industry Corporation(2019-HT-XG)Foundation of Aeronautics Science Fund(2017ZF53071)the School-enterprise Collaborative Innovation Fund for Graduate Students of Northwestern Polytechnical University(XQ201913)。
文摘Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value.In this work,the wood-derived porous carbon(WPC)skeleton from natural wood was performed as a template.And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites,based on highly ordered honeycomb cells inner WPC as a microreactor.Higher carbonization temperature is more conducive to the graphitization degree of natural wood.MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 d B at density as low as 0.197 g/cm^3.Such wall-like"mortar-brick"structures(WPC skeleton as"mortar"and MXene aerogel as"brick")not only effectively solve the unstable structure problem of MXene aerogel networks,but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy,thereby exhibiting the superior EMI shielding performance.In addition,MXene aerogel/WPC composites also exhibit good anisotropic compressive strength,excellent thermal insulation and flame retardant properties.Such ultra-light,green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry,etc.
文摘Metal-organic frameworks are compounds with a reticulated skeletal structure formed by chemically bonding inorganic and organic units that are widely used in many fields, such as photocatalysis, gas separation and energy storage, because of their unique structures. In this paper, we prepared a metal-organic framework [(<em>μ</em><sub>2</sub>-2-methylimidazolyl)<sub>12</sub>-Zn(ii)<sub>6</sub>-H<sub>18</sub>O<sub>10</sub>]<sub>n</sub>(ZM) with well-developed pores and high specific surface area of MOFs by the solution method. And MOF-derived porous carbon was prepared by the direct charring method in an argon atmosphere using a mixture of ZM, ZM and potassium citrate as carbon precursors. Characterization analysis revealed that the maximum specific surface area of ZMPC-800-1:15 was 2014.97 m<sup>2</sup><span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, and the pore size structure was mainly mesoporous. At a current density of 1.0 A<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup> the specific capacitance of ZMC-800 and ZMPC-800-1:15 was 121.3 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup> and 226.6 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, respectively, with a substantial increase of 86.8%. The specific capacitance of ZMPC-800-1:15 decays to 168.8 F<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>, with a decay rate of 25.5%, when the current density increases to 10.0 A<span style="white-space:nowrap;">⋅</span>g<sup><span style="white-space:nowrap;">−</span>1</sup>. After 5000 constant current charge/ discharge cycles, the capacitance retention rate was still 96.41%. These results prove that the application of MOF-derived carbon materials in future supercapacitors is very promising.
