低维纳米材料颗粒尺寸小、比表面积大且具有区别于体材料的量子限域效应等特点，使其表现出比体材料更丰富、新颖的物理、化学特性。本论文采用化学合成方法制备二硫化钼纳米片、石墨烯、碳纳米管及其复合材料，通过调控材料的维度、尺寸、异质组分和界面结构等，研究材料低维化和复合结构对其电磁响应的影响，力图揭示其电磁衰减机制，为其它低维材料的结构设计与研发提供理论支持。同时，针对所制备的低维材料，开展了锂/钠离子电池负极材料的研究。论文取得的研究结果如下： (1)采用锂插层剥离方法制备了二维二硫化钼纳米片(MoS₂-NMS)吸波材料，研究了材料维度的降低对其介电和吸波性能的影响。相同条件下，MoS₂-NMS的介电虚部是块体二硫化钼的两倍。研究认为，MoS₂-NMS中存在部分金属态1T相以及大量缺陷偶极子，增强了材料的微波介电损耗。60wt%填充量、2.4㎜厚度下， MoS₂-NMS的最大电磁衰减(RL〓)可达-39dB，有效吸波带宽(EAB)为4.1GHz。 (2)采用热还原方法制备了二维氮掺杂石墨烯(NG)吸波材料，研究了不同氮掺杂含量对石墨烯的介电和吸波性能的影响规律。氮掺杂的引入可以提升材料的偶极子极化损耗和电导损耗，并改善材料的阻抗匹配特性。NG-100样品在10wt%填充量、2.5㎜厚度下的RL〓可达-50dB，EAB为8 GHz。 (3)设计并制备了石墨烯与二硫化钼纳米片层层复合的2D/2D结构型吸波材料，研究了异质界面的引入对材料介电和吸波性能的影响。NMS/rGO样品中在低填充量下，界面极化损耗对材料的介电损耗贡献显著；高样品填充量下，漏电损耗占主导。与单一的NMS或者rGO相比，2D/2D结构型材料展现出优异的吸波性能。 (4)采用热解法制备了碳纳米管包覆铁、钴、镍金属(M@NCNTs，M=Fe、Co、 Ni)和Fe/Fe₃C(Fe/Fe₃C@NCNTs)两种0D/1D结构型吸波村料。此两种0D/1D结构型材料作为吸波材料时，界面极化损耗和电导损耗是其主要损耗机制。Fe@NCNTs在填充量为10wt%、厚度为3.2㎜时，RL〓可达-30.43dB，EAB为5.76dB。 (5)将Fe/Fe₃C@CNTs分别在空气或者硫(S)氛围下高温处理，制备了Fe₂O₃@CNTs锂负极和Fe〓S@CNTs钠负极材料。Fe₂O₃@CNTs在500mA/g电流密度下循环200次后的比容量仍可达900mAh/g，表现出较好的循环稳定性，这归结于CNTs包覆对充放电过程体积变化较大的Fe₂O₃的稳定作用以及形成了稳定的SEI膜。 Fe〓S@CNTs在100mA/g电流密度下循环180次后的比容量为520mAh/g，显示出良好的钠电循环倍率性能。 (6)采用冰模板方法制备了电化学窗口大、离子电导率高、热稳定性和电化学稳定性高、机械性能优异的LATP-PEO柔性固态电解质。相比较于聚合物电解质，垂直排列的LATP可以有效提供锂离子通道，室温下电导率可达0.52*10⁻⁴S/㎝。 关键词：二硫化钼纳米片；石墨烯；CNTs；微波介电性能；微波吸收；锂/钠电池负极材料

 The low dimensional nanomaterials have received significant investigation on their peculiar physicochemical properties resulting from their nano-size, higher specific surface area and quantum confinement effect. In this paper. MoS₂ nanosheets, graphene, carbon nanotubes and their composites were prepared by chemical synthesis methods. By tuning the dimension, components, sizes and interfacial structures of composites, the dielectric and microwave absorption performance were studied and the corresponding attenuation mechanisms were discussed. This paper provides theoretical support for structural design and electromagnetic parameter optimization of novel microwave absorption materials. At the same time, the prepared low dimensional materials were studied as anode materials of lithium/sodium ion batteries. The main results of this paper are as follows: (1) Few-layered MoS₂ nanosheets (MoS₂-NMS) were obtained via the top-down exfoliation method from bulk MoS₂ (MoS₂-Bulk). The dimension-dependent dielectric properties and microwave absorption performance of MoS₂ were investigated by presenting a comparative study between MoS₂-NMS and MoS₂-Bulk. Under the same mass loading, the imaginary permittivity (ε") of MoS₂-NMS/wax is twice as large as that of MoS₂-Bulk/wax, which is attributed to the existence of metallic 1T phase and defect dipoles in MoS₂-NMS. The minimum reflection loss (RL) value of MoS₂-NMS/wax with 60 wt% loading is -38.42 dB under 2.4 ㎜, and the corresponding bandwidth with effective attenuation (< -10 dB) is up to 4.1 GHz. (2)Nitrogen-doped graphene (NG) with different nitrogen contents (0 wt%, 4.4 wt% and 9.1 wt%) were prepared via hydrothermal reaction of GO with urea. The effect of nitrogen content on complex permittivity and microwave absorption performance of NG were investigated. Compared to non-doped rGO. the NG sample achieves a better balance between the attenuation factor "α" and impedance matching "Δ" and thus leads to the best EMW absorbing performance. The maximum RL of NG-100 with 10 wt% loading is up to ～-50 dB and the EAB is as wide as 8 GHz under 2.5 ㎜. (3)By using a simple moderate reduction mixing process, layer by layer hierarchical architectures of NMS and reduced graphene oxide (rGO) (2D/2D-NMS/rGO) were prepared. It is found that the introduced 2D/2D interfacial architectures has a positive effect on the dielectric properties and microwave absorption performance of composites. For NMS/rGO-5:l and NMS/rGO-10:1 samples with (5-30) wt% loading, as well as NMS/rGO-2:1 with (5-25) wt% mass loading, the interfacial polarization loss are dominant in the whole dielectric relaxation loss of composites. For NMS/rGO-2:1 with 30 wt% loading, the leakage loss becomes dominant. The 2D/2D NMS/rGO presents excellent EMW absorbing performance with respect to pure NMS or rGO. (4)By using a modified non-toxic pyrolysis method, M@NCNTs comprising in-situ formed M nanoparticles (M=Fe, Co, Ni, Fe/Fe₃C) encapsulated in nitrogen-doped carbon nanotubes (NCNTs) (0D/1D) were prepared. The interfacial polarization loss and conduction loss are the main attenuation mechanisms in samples. The minimum RL of Fe@NCNTs (10 wt% loading) is up to 30.43 dB at 3.2 ㎜, and the effective absorption bandwidth is as wide as 5.7 GHz. (5)The Fe₂O₃@CNTs and Fe〓S@CNTs were prepared by annealing Fe/Fe₃C@CNTs under air or sulfur atmosphere and evaluated as anodes of lithium battery (LIBs) or sodium battery (SIB). When used as anode of LIBs, Fe₂O₃@CNTs shows high cycling stability, enhanced rate capacity and long cycling performance. The Fe₂O₃@CNTs delivers high specific capacity of 900 mAh/g after 200 cycles at 500 mA/g. The structure of Fe₂O₃@CNTs can avoid the direct contact between Fe₂O₃and electrolyte effectively. As a result, the stable SEI film can be formed on the surface of the electrode. In addition, the CNTs in Fe₂O₃@CNTs can provide enough space for alleviating the volume expansion of Fe₂O₃during cycling process. When used as anode of SIBs, the Fe〓S@CNTs delivers high specific capacity of 520 mAh/g after 180 cycles at 100 mA/g. (6)The LATP-PEO solid composite electrolyte was prepared by ice-templating method, which has a larger electrochemical window, higher ionic conductivity, geometric and electrochemical stability. Compared to the pure polymer electrolyte, the aligned structure of LATP-PEO solid composite electrolyte provides direct channels for lithium ions transport and the ionic conductivity reaches as high as 0.52* 10⁻⁴ S/㎝, indicating its promising practical potentials in energy storage area. Key Words: Molybdenum disulfide nanosheets; Graphene; CNTs; Microwave dielectric properties; Microwave absorption performance; Anode materials of Lithium/Sodium-ion batteries