The fabrication of high-performance electromagnetic (EM) wave absorption (EMA) materials is an effective strategy to deal with ever-increasing EM pollution. In this work, a series of manganese oxides/porous carbon (Mn_xO_y@C) hybrid composites are obtained by a two-step process. It is revealed that different manganese oxides play various influence on the dielectric properties of absorbers. Owing to the moderate complex permittivity of MnO@C hybrid composites, the optimal reflection loss could reach as high as -76.0 dB at the matching thickness of 2.0 mm with 5.2 GHz of effective absorption bandwidth at thickness of 2.1 mm. We demonstrated that the addition of porous carbon is vital for enhancing EMA performance of composites, which not only coordinates impedance matching allowing more EM waves enter the absorber, but also provides the path for electron movement, thus profiting conductive loss. Besides, different heterogeneous interfaces including porous carbon, manganese oxide and so on, are conducive to contribution of interface polarization. The most noteworthy is ingenious design of composite materials and systematic research of EM energy attenuation mechanism in this work will provide the possibility to realize high-performance EMA.

高性能电磁 (EM) 波吸收 (EMA) 材料的制造是应对不断增加的电磁污染的有效策略。在这项工作中，一系列锰氧化物/多孔碳（Mn _x O _y@C) 混合复合材料是通过两步法获得的。结果表明，不同的锰氧化物对吸收体的介电性能有不同的影响。由于 MnO@C 杂化复合材料的复介电常数适中，在 2.0 mm 的匹配厚度和 5.2 GHz 的有效吸收带宽下，最佳反射损耗可高达 -76.0 dB，厚度为 2.1 mm。我们证明了添加多孔碳对于提高复合材料的 EMA 性能至关重要，它不仅协调阻抗匹配允许更多的 EM 波进入吸收体，而且还为电子运动提供了路径，从而有利于传导损耗。此外，不同的异质界面包括多孔碳、氧化锰等，有利于界面极化的贡献。