Combination of carbon and metal materials is a good strategy to develop lightweight microwave absorbents. Taking advantage of the encapsulation property of carbon nanoflakes, a stable microwave absorber could be achieved. In this study, we managed to achieve sandwich-shaped Ni/C nanoflakes via a simple route involving a one-step hydrothermal method towards Ni(OH)₂ nanosheets, followed by a calcination procedure. These sandwiched carbon nanoflakes not only increased the interfacial polarization, but also resulted in the absolute stability of metal nanoparticles. Considering the higher possibility of some support plates to be wrinkled, which would bring about imperfect sandwiched structures, the free-standing sandwiched composites were in a relatively good shape. Furthermore, the intensive conductive loss could be highly responsible for better microwave absorption properties by adjusting the carbonization temperature. The minimum reflection loss (RL) value of Ni/C composites that were obtained with a 25% loading filler ratio could reach −24.3 dB with a matching thickness of only 1.5 mm. Moreover, the effective microwave absorption bandwidth (<−10 dB) could reach to 4.0 GHz with thicknesses of both 1.3 mm and 1.4 mm. Therefore, the sandwich-shaped Ni/C nanoflakes could be exploited as an effective and lightweight microwave absorber.

中文翻译：

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将金属纳米颗粒包裹在碳纳米薄片中：由独立式夹心复合材料设计的稳定吸收剂

碳和金属材料的结合是开发轻型微波吸收剂的好策略。利用碳纳米薄片的封装特性，可以实现稳定的微波吸收剂。在这项研究中，我们设法通过简单的方法获得夹心形状的Ni / C纳米片，该方法涉及对Ni（OH）₂的一步式水热法纳米片，然后进行煅烧程序。这些夹在中间的碳纳米片不仅增加了界面极化，而且还导致了金属纳米粒子的绝对稳定性。考虑到某些支撑板起皱的可能性更高，这会导致不理想的夹层结构，因此，独立式夹层复合材料的形状相对较好。此外，通过调节碳化温度，强烈的传导损耗可能是导致更好的微波吸收性能的重要原因。以25％的填充填料比例获得的Ni / C复合材料的最小反射损耗（RL）值可以达到-24.3 dB，而匹配厚度仅为1.5 mm。此外，厚度均为1时，有效微波吸收带宽（<-10 dB）可以达到4.0 GHz。3毫米和1.4毫米。因此，夹层状的Ni / C纳米薄片可以用作一种有效且轻巧的微波吸收剂。