Coal-derived carbon nanomaterials for sustainable energy storage applications
摘要: 煤炭清洁高效利用是煤炭产业精细化、高值化发展的必由之路。作为自然界广泛存在的高碳资源，以煤炭为原料开发煤基新型炭材料，拓展煤炭利用新途径是一个具有前景而富有挑战性的课题。近年来，研究者以煤炭及其衍生物为含碳前驱体，设计并构筑了具有丰富形态和结构的纳米炭材料，进一步考察了其在储能、催化、吸附与分离等领域的应用。本文综述了基于煤炭及其衍生物开发新型炭纳米材料的最新研究进展，重点介绍了针对不同煤阶煤制备炭纳米材料的设计合成方法和结构调控策略，讨论了煤基炭纳米材料在二次电池和超级电容器为主的储能过程中的应用。最后，对煤炭材料化利用的未来发展进行了展望，以期为先进煤衍生炭纳米材料的精细设计和可控制备等方面提供新的研究思路。Abstract: As a natural abundant high-carbon resource, the use of coal to develop carbon nanomaterials is an important research topic. In recent years, a variety of carbon materials with different morphologies and nanotextures have been designed and constructed using coal and their derivatives as precursors, and their use in energy storage, catalysis, adsorption and absorption have been explored. State-of-the-art research on carbon nanomaterials derived from coals of different rank and their derivatives are summarized with specific attention to the synthesis strategies and structure control. The use of these coal-derived carbons for energy storage, such as secondary batteries and supercapacitors, is also discussed in terms of their structural features. The review aims to provide valuable insight into the present challenges and inspire new ideas for the development of advanced coal-derived carbon materials.
Figure 2. (a) Macroscale image and illustrative nanostructure of coal. (b) SEM image of ground bituminous coal, (c) Schematic illustration of the synthesis of b-GQDs (Oxygenated sites are shown in red), (d) TEM image of b-GQDs showing a regular size and shape distribution,(e) HRTEM image of representative b-GQDs from (d) (the inset is the 2D FFT image that shows the crystalline hexagonal structure of these quantum dots) and (f) AFM image of b-GQDs showing height of 1.5−3 nm. Reprinted with permission.
Figure 3. (a) Schematic illustration of C-GQDs synthesis, (b) TEM image of C-GQDs, (c) HRTEM image of C-GQDs. Inset is the FFT pattern of C-GQDs. Reprinted with permission.
Figure 4. TEM images of iron carbide-oxide filled CNTs obtained via CVD of coal-gas: (a) low-resolution TEM image of partly filled CNTs and (b) high-resolution TEM image of one filled CNT. Reprinted with permission.
Figure 5. (a, b, c) FESEM images of CPCFs at low magnification: PVA/Coal = (a) 2/1, (b) 1/1 and (c) 1/2 and (d, e, f) magnified FESEM images of CPCFs: PVA/Coal = (d) 2/1, (e) 1/1 and (f) 1/2. Reprinted with permission.
Figure 6. (a) Raman spectra of coal derived graphene film synthesized at 1055 oC for 30 min, (b) Large area of coal derived graphene films on TEM grid, (Inset: SAED with six diffraction spots demonstrating crystalline nature of coal derived graphene film), (c) High magnification TEM image with the edge of the coal derived graphene film and (d) schematic of growth mechanism of coal derived graphene films . Reprinted with permission.
Figure 7. (a, b) Digital photos of samples before and after treatment with H2 discharge plasma, and SEM and TEM images of (c, d, e) TX-NC-GS (graphene sheets obtained from Taixi coal without catalytic graphitization) and (f, g, h) TX-C-GS (graphene sheets obtained from Taixi coal with catalytic graphitization,) with different magnifications. Reprinted with permission.
Figure 8. (a, b) FESEM images of ISPCs and (c, d) TEM images of ISPCs. Reprinted with permission.
Figure 9. (a) CV curves of PCNS1000 between 0.01 and 2.8 V at 0.1 mV s−1, (b) Galvanostatic discharge-charge profiles of PCNS1000 at 100 mA g−1, (c) Rate capability of the electrodes at different current densities, (d) Cycling performance of the electrodes at 0.5 A g−1 and (e) Long-term cycling stability of PCNS1000 at 2 A g−1. Reprinted with permission.
Figure 10. (a) CV curves under the scan rate of 10 mV s−1, (b) Galvanostatic charge-discharge curves under 1 A g−1 of the HPCNs prepared with different template addition ratios, (c) CV curves of the HPCN-1∶3 under different scan rates from 10 to 500 mV s−1, (d) The rate performance, (e) The cycle performance under 10 A g−1, (f) The EIS spectra of the HPCNs prepared with different template addition ratios. Reprinted with permission.
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