东华大学《Adv Sic》：基于MOF衍生的多孔碳纳米复合材料，可打破块状石墨的导电性和机械强度之间的权衡

图1、 a) Schematic illustration for the fabrication process of C/CoB. b) XRD patterns of ZIF-67 and C/Co. c) XRD patterns of C/CoB prepared at different sintering temperatures. d) Raman spectra with I D /I G values of C/CoB-1400, C/CoB-1600, C/CoB-1800, and C/Co. e–g) Cross-section SEM images of C/CoB-1400, C/CoB-1600, and C/CoB-1800. h–j) C 1s, Co 2p, and N 1s XPS spectra of C/Co and C/CoB-1800.

图2、Microstructural characterizations and chemical structure of C/CoB-1800. a) TEM image. b) Detailed magnified TEM image. c) HRTEM image. d) Detailed magnified HRTEM image. e) HAADF-STEM image of carbon matrix regions. f-f 1 ) Elemental mapping images of Co, N, C, and O. g) Detailed magnified HAADF-STEM image of Co. h) Co K -edge XANES spectra, i) EXAFS spectra in R space of Co foil, CoPc, Co 3 O 4 , CoO, and C/CoB-1800. j) Co k 3 χ(k) oscillation curves, k) Fourier transform of the EXAFS spectra and the corresponding fitting curve of C/CoB-1800. l–o) Wavelet transforms (WT) of CoO, Co foil, CoPc, and C/CoB-1800.

图3、a) Flexural strength, b) Compressive strength of C/CoB-1400, C/CoB-1600 and C/CoB-1800. c) Density and relative densities of C/CoB at different sintering temperatures. d) Radar map comparison of physical properties between commercial HPBGs and C/CoB-1800 (Table S4 , Supporting Information). e) Schematic illustration of the microstructure of C/CoB.

图4、 EMI shielding performance of C/CoB-1800 in the a) X-band, b) Ku-band, and c) K-band. d) The R, T, and A coefficients of C/CoB-1800. e) The compressive strength and EMI SE T value of C/CoB-1800 compared with reported carbon-based EMI shielding bulks (Table S9, Supporting Information). f) EMI shielding performance and electrical conductivity of typical bulk materials compared with C/CoB-1800 (Table S7, Supporting Information).

图5、a) The temperature-time curves of C/CoB-1800 at different input voltages. b) Infrared images of C/CoB-1800 at various input voltages. c) Experimental data and linear fitting of surface temperature to U 2 . d) Cyclic stability of C/CoB-1800 at cycles 5 and 10 at 0.8 V. e) Surface temperature of C/CoB-1800 with gradient voltage variation. f) Distribution diagram of the relationship between wood thickness and surface temperature at 0.8 V energized for 5min. g) Infrared images of the surface temperature of the back of the wooden board with various thicknesses. h) Schematic diagram of a bulk used for modeling wood floor heaters in houses. i) Images depicting changes in an incandescent bulb without or with the C/CoB-1800 under the influence of a Tesla coil. j) Electric and magnetic field values of the house before and after the installation of the C/CoB-1800.

本研究证明了 MOF 衍生的多孔碳复合材料作为高能前驱体的潜力，可用于轻松制造具有优异导电性和较强机械强度的石墨复合材料块。作为概念验证，我们使用了由钴基 MOF 原型ZIF-67制成的嵌入Co NPs 的纳米多孔碳。在烧结过程中，多孔碳骨架在Co NPs 的催化作用下迅速塌陷，并在原位组装成密集的多层石墨烯薄片。分散的 Co NPs 提供了强大的层间粘附力和相互作用力，增强了平面内和平面外的导电性，防止了沿致密平面的裂解。耐人寻味的是，Co NPs在石墨晶格相中以单个原子和团簇的形式进行部分扩散，进一步促进了电子的有效迁移

因此，由此产生的石墨复合大块具有显著的导电性，面内和面外导电值分别达到 7311 S cm-1 和 5541 S cm-1。此外，石墨复合材料还具有足够的机械强度，抗折和抗压强度分别达到 101.17±5.73 兆帕和 151.56±2.53 兆帕。高度有序的石墨结构进一步赋予石墨复合材料体以卓越的热导率，在 423 K 时，其平面内热导率峰值达到 248 Wm-¹K-¹。鉴于其卓越的综合性能，我们进行了实际应用演示，以突出这些坚固材料在需要卓越电磁干扰屏蔽和高效加热的应用中的巨大潜力。块状石墨复合材料表现出高效的 EMI 屏蔽性能，在 X、Ku 和 K 波段的屏蔽值分别为 68.26、53.52 和 32.45 dB。此外，块状复合材料还表现出卓越的焦耳热效应，在电压仅为 1.0V 的情况下，表面温度达到 80.2 °C。我们预计，本研究中开发的材料以及利用源自 MOF 的多孔碳作为高性能块状石墨的创新原材料的概念，代表着在设计用于纳米机械、航空航天、电子等领域的各种应用的强导电材料方面取得了重大进展。