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[Display omitted] • Flower-like bimetallic MOF-derived carbon composites. • Regulate structures by adjusting different precursor ratios. • High-efficiency microwave absorption of −56.89 dB with wide bandwidth of 4.7 GHz. • Synergistic effect of unique structure and electromagnetic characteristic for EWA. Recently, high-performance functional composites for electromagnetic wave absorption (EWA) with tunable nano/micro-structures have attracted extensive attention. Herein, the flower-like electrically conductive and magnetic cobalt-nickel@carbon (CoNi@C) composites derived from bimetallic metal-organic frameworks (MOFs) were fabricated via solvothermal method and pyrolysis. By adjusting the ratios of different precursors, different morphological features of composites were formed. When the molar ratio of Co and Ni was 1:2, the CoNi@C composites exhibited the optimal minimum reflection loss (RL min) of −56.89 dB at 6.7 GHz with an effective absorption bandwidth of 4.7 GHz, due to the coordinated dielectric and magnetic loss caused by the electromagnetic properties of each component as well as the interactions between the unique three-dimensional (3D) interfaces of flower-like structures that promoted the absorption and dissipation of composites for microwaves. The composites are expected to become promising candidates as high-efficiency absorbers in the electromagnetic protection field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like bimetallic MOF-derived carbon composites. • Regulate structures by adjusting different precursor ratios. • High-efficiency microwave absorption of −56.89 dB with wide bandwidth of 4.7 GHz. • Synergistic effect of unique structure and electromagnetic characteristic for EWA. Recently, high-performance functional composites for electromagnetic wave absorption (EWA) with tunable nano/micro-structures have attracted extensive attention. Herein, the flower-like electrically conductive and magnetic cobalt-nickel@carbon (CoNi@C) composites derived from bimetallic metal-organic frameworks (MOFs) were fabricated via solvothermal method and pyrolysis. By adjusting the ratios of different precursors, different morphological features of composites were formed. When the molar ratio of Co and Ni was 1:2, the CoNi@C composites exhibited the optimal minimum reflection loss (RL min) of −56.89 dB at 6.7 GHz with an effective absorption bandwidth of 4.7 GHz, due to the coordinated dielectric and magnetic loss caused by the electromagnetic properties of each component as well as the interactions between the unique three-dimensional (3D) interfaces of flower-like structures that promoted the absorption and dissipation of composites for microwaves. The composites are expected to become promising candidates as high-efficiency absorbers in the electromagnetic protection field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-light carbon nanofiber aerogels assisted by bimetal-organic frameworks. • Enhanced microwave absorption of −66.57 dB and super-wide absorption bandwidth. • Long-term thermal stability with super-fast Joule heating (cooling) rate. Lightweight carbon-based aerogels with fast heat dissipation capability are promising electromagnetic wave absorber materials for developing integrated electronics, artificial intelligence, and human-interaction equipment under harsh thermal environments. Herein, the bimetallic (cobalt (Co) and nickel (Ni)) metal–organic frameworks (CoNi-MOFs), cellulose nanofibrils (CNFs), and aramid nanofibers (ANFs) were assembled into a conductive and magnetic CoNi@carbon/ANF/CNF carbon composite aerogel (CoNi@C/ACA) with an ultra-low density of 6.15 mg/cm3 using freeze-drying and subsequent carbonization treatment. Owing to the synergistic effects of multiple reflections inside the three-dimensional interconnected structures, abundant interfacial/dipolar polarizations, and coordinated dielectric and magnetic losses, the CoNi@C/ACA achieved a fascinating minimum reflection loss value of −66.57 dB and broad effective absorption bandwidth up to 6.3 GHz, which were characterized with an ultra-low loading of 1.8 wt%. In addition, it displayed good thermal stability with a super-fast Joule heating (cooling) rate at low driving voltages. These unique characteristics of the ultra-light CoNi@C/ACA make it a promising material for demanding applications, e.g. , electromagnetic pollution elimination and thermal management. [ABSTRACT FROM AUTHOR]