Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic (EM) waves. Thus, directional electromagnetic interference (EMI) shielding materials (i.e., when the EM wave is incident from different sides of the sample, the EMI shielding effectiveness (SE) is rather different) are strongly required; unfortunately, no comprehensive literature report is available on this research field. Herein, Ni-coated melamine foams (Ni@MF) were obtained by a facile electroless plating process, and multiwalled carbon nanotube (CNT) papers were prepared via a simple vacuum-assisted self-assembly approach. Then, step-wise asymmetric poly(butylene adipate-co-terephthalate) (PBAT) composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation approach. The step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding performances. When the EM wave is incident from Ni@MF layer or CNT layer, Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE (SE_T) of 38.3 and 29.5 dB, respectively, which illustrates the ΔSE_T of 8.8 dB. This work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures, which has promising applications in portable electronics and next-generation communication technologies.

一些精密电子产品（例如信号发射器）不仅需要发出有效信号，还需要受到保护以免受外部电磁（EM）波的影响。因此，强烈需要定向电磁干扰（EMI）屏蔽材料（即当电磁波从样品的不同侧面入射时，EMI屏蔽效能（SE）有较大差异）；不幸的是，目前还没有关于该研究领域的综合文献报告。在此，通过简单的化学镀工艺获得了镀镍三聚氰胺泡沫（Ni@MF），并通过简单的真空辅助自组装方法制备了多壁碳纳米管（CNT）纸。然后，通过简便的溶液封装方法成功制备了由松散的Ni@MF层和致密的CNT层组成的逐步不对称聚己二酸-对苯二甲酸丁二醇酯（PBAT）复合材料。阶梯式不对称结构和导电性赋予Ni@MF/CNT/PBAT复合材料前所未有的定向EMI屏蔽性能。当电磁波从 Ni@MF 层或 CNT 层入射时，Ni@MF-5/CNT-75/PBAT 的总 EMI SE (SET _T ) 分别为 38.3 和 29.5 dB，这表明 ΔSE _T为 8.8分贝。这项工作为具有阶梯式不对称结构的定向 EMI 屏蔽复合材料打开了一个新的研究窗口，该复合材料在便携式电子产品和下一代通信技术中具有广阔的应用前景。