The widespread application of high-frequency electronic and communication devices has caused increasingly severe electromagnetic pollution. It is highly desirable but challenging to develop ultralight electromagnetic wave (EMW) absorbers with strong absorption performance to eliminate the negative effects of electromagnetic pollution. Herein, a secondary ion adsorption and defect-anchoring strategy was proposed to construct ultralight N-doped graphene aerogels containing isolated single cobalt atoms (Co-SAs/GAs) with a tunable content of Co-SAs from 1.13 to 2.58 wt. %. The optimal Co-SAs/GAs with a matching thickness of 1.5 mm and an ultralow filler ratio of 5 wt. % attenuated about 99.999% electromagnetic energy and exhibited specific EMW absorption performance (SMAP) of 37 220 dB cm² g⁻¹, which was 15 000 dB cm² g⁻¹ higher than that of the best reported absorber in literature. Permittivity and electrical conductivity measurements indicated that the introduction of Co-SAs significantly increased the conduction and polarization losses of the GAs, which was confirmed by simulation results based on the Havriliak–Negami equation. Theoretical calculations demonstrated that the Co–N₄ moiety exhibited obvious polarization behavior, which could be further tuned by defective sites in its vicinity. This comprehensive investigation of the relationships between single-atom structure and electromagnetic wave absorption property provides an efficient route toward the rational design of ultralight absorbers with metal single-atoms.

中文翻译：

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原子分散钴锚定在 N 掺杂石墨烯气凝胶上，以超低填料比实现高效电磁波吸收

高频电子和通信设备的广泛应用造成了日益严重的电磁污染。开发具有强吸收性能的超轻电磁波（EMW）吸收剂以消除电磁污染的负面影响是非常可取但具有挑战性的。在此，提出了一种二次离子吸附和缺陷锚定策略来构建超轻 N 掺杂石墨烯气凝胶，该气凝胶含有孤立的单钴原子 (Co-SAs/GAs)，Co-SAs 的含量可从 1.13 到 2.58 wt。%。最佳 Co-SAs/GAs 匹配厚度为 1.5 mm，超低填料比为 5 wt。% 衰减了约 99.999% 的电磁能量，并表现出 37 220 dB cm ²  g ^{-1的特定 EMW 吸收性能 (SMAP)}，这比文献中报道的最好的吸收器高15 000 dB cm ²  g ^{-1 。}介电常数和电导率测量表明，Co-SAs 的引入显着增加了 GAs 的传导和极化损耗，这通过基于 Havriliak-Negami 方程的模拟结果得到证实。理论计算表明，Co-N ₄部分表现出明显的极化行为，可以通过其附近的缺陷位点进一步调整。这种对单原子结构与电磁波吸收特性之间关系的全面研究为合理设计具有金属单原子的超光吸收器提供了一条有效途径。