High-temperature pyrolysis of metal–organic framework (MOF) is an effective way to prepare lightweight and high-performance electromagnetic wave absorbers. In this work, iron cobalt nickel/carbon (FeCoNi/C) decorated graphene composites were fabricated by the two-step method of solvothermal reaction and pyrolysis treatment. Results of micromorphology analysis demonstrated that numerous octahedral FeCoNi/C carbon frameworks were almost uniformly distributed on the wrinkled surfaces of flaky graphene. Moreover, the electromagnetic parameters and wave absorbing properties of obtained composites were regulated through simply changing the addition amounts of graphene oxide. Significantly, the as-prepared FeCoNi/C decorated graphene composite with the addition amount of graphene oxide of 67.2 mg exhibited the best electromagnetic absorption performance. The minimum reflection loss was as large as −66 dB at 15.6 GHz and broad absorption bandwidth reached up to 4.8 GHz with an ultrathin thickness of 1.53 mm and a filler loading ratio of 30 wt%. Furthermore, the maximum absorption bandwidth was enlarged to 5.2 GHz via slightly adjusting the matching thickness to 1.56 mm. Additionally, the probable electromagnetic attenuation mechanisms of attained composites were proposed. The results of this study would provide a reference for the preparation of MOF derived carbon-based magnetic composites as ultrathin and high-performance electromagnetic absorbers.

金属有机骨架（MOF）的高温热解是制备轻质、高性能电磁波吸收体的有效途径。在这项工作中，通过溶剂热反应和热解处理两步法制备了铁钴镍/碳（FeCoNi/C）修饰的石墨烯复合材料。微观形态分析结果表明，许多八面体 FeCoNi/C 碳骨架几乎均匀分布在片状石墨烯的褶皱表面上。此外，通过简单地改变氧化石墨烯的添加量，可以调节所得复合材料的电磁参数和吸波性能。值得注意的是，所制备的氧化石墨烯添加量为 67.2 mg 的 FeCoNi/C 装饰石墨烯复合材料表现出最佳的电磁吸收性能。最小反射损耗在 15.6 GHz 时高达 −66 dB，宽吸收带宽达到 4.8 GHz，超薄厚度为 1.53 mm，填料负载率为 30 wt%。此外，通过将匹配厚度略微调整至 1.56 mm，最大吸收带宽扩大至 5.2 GHz。此外，还提出了所得复合材料可能的电磁衰减机制。该研究结果将为制备MOF衍生的碳基磁性复合材料作为超薄高性能电磁吸波材料提供参考。通过将匹配厚度微调至1.56 mm，最大吸收带宽扩大至5.2 GHz。此外，还提出了所得复合材料可能的电磁衰减机制。该研究结果将为制备MOF衍生的碳基磁性复合材料作为超薄高性能电磁吸波材料提供参考。通过将匹配厚度微调至1.56 mm，最大吸收带宽扩大至5.2 GHz。此外，还提出了所得复合材料可能的电磁衰减机制。该研究结果将为制备MOF衍生的碳基磁性复合材料作为超薄高性能电磁吸波材料提供参考。