The hexaferrite materials have been regarded as a promising candidate for the advanced electromagnetic wave absorbing (EMA) materials. Meanwhile, the flower-like morphological and hierarchical structure has been widely accepted as a critical technique to achieve both lower reflection loss (RL) and wider qualified bandwidth (QB, RL ≤ −10 dB) due to the induced multiple scattering and electromagnetic loss abilities for microwave absorption. In this study, core-shell nanostructure composites of Co₂Y@MnO₂@CNTs have been successfully synthesized by a facile one-step hydrothermal method, in which the Ba₂Co₂Fe₁₂O₂₂ (Co₂Y) nanoparticles are wrapped in the carbon nanotubes (CNTs) attached hollow MnO₂ microflowers. Results show that the surface morphology can be well controlled by modulating the mass ratio of Co₂Y and MnO₂ reactants, and the characteristic impedance can be greatly improved through the precise tuning of the conductive CNTs attachments. An ultra-wide QB value of 15.7 GHz (2.3–18 GHz) is realized within an integrated thin thickness from 1.0 to 5.0 mm, which means the composite shows excellent EMA performance in the S, C, X, and Ku band with relatively thin sample thicknesses. For example, the RL_min reached −22.6 dB at 12.6 GHz with a QB of 7.22 GHz at 1.63 mm in the Ku band, and −40.4 dB at 3.28 GHz with a QB of 3.47 GHz at 4.87 mm in the S and C band. Besides the outstanding microwave absorbent candidates, this work has also developed a novel and more generalized approach to promoting the ferrite-based high-performance EMA application by delicate nanostructure and composition design.

六铁氧体材料被认为是先进的电磁波吸收（EMA）材料的有前途的候选材料。同时，由于诱导的多重散射和电磁损耗能力，像花一样的形态和层次结构已被广泛接受为实现更低的反射损耗（RL）和更宽的合格带宽（QB，RL≤-10 dB）的关键技术。用于微波吸收。本研究通过一种简便的一步水热法成功制备了Co ₂ Y @ MnO ₂ @CNTs的核壳纳米结构复合材料，其中Ba ₂ Co ₂ Fe ₁₂ O ₂₂（Co ₂Y）纳米粒子包裹在附着在中空MnO ₂微型花的碳纳米管（CNT）中。结果表明，通过调节Co ₂ Y和MnO ₂反应物的质量比，可以很好地控制表面形貌，并且通过精确调节导电CNTs的附着量可以大大提高特性阻抗。在1.0至5.0 mm的集成薄厚度范围内，实现了15.7 GHz（2.3-18 GHz）的超宽QB值，这意味着该复合材料在S，C，X和Ku波段显示了出色的EMA性能，且厚度相对较薄样品厚度。例如，RL_分钟在Ku频段1.63 mm处的QB为7.22 GHz时，在12.6 GHz时达到-22.6 dB，在S和C频段4.87 mm处的QB为3.47 GHz时在3.28 GHz时达到-40.4 dB。除了出色的微波吸收剂候选产品之外，这项工作还开发了一种新颖且更通用的方法，通过精细的纳米结构和成分设计来促进基于铁氧体的高性能EMA应用。