图1.石墨阳极电极、阴极电极和阵列电解槽的示意图，用于通过电化学剥离放大生产石墨烯。
图2. Optical images of (a) bare cathode/anode, (c) encapsulated anode, and (e) encapsulated cathode/anode after the exfoliation along with corresponding (b, d, f) electrolytes, respectively; (g) electrolyte temperature curve and (h) current curve along with time; and (i) exfoliation efficiency and (j) graphene yield of different electrodes.
图3. (a) XRD patterns, (b) Raman spectra, (c) FT-IR spectra, and (d) XPS high-resolution C 1s spectra of graphene products obtained from bare cathode/anode, encapsulated anode, and encapsulated cathode/anode electrodes.
图4、(a) Real-time voltage curves, (b) contact angles of the graphite foil surface at different exfoliation times, (c) real-time current curves, (d) exfoliation efficiency and graphene yield, (e) XRD spectra of graphene, and (f) real-time electrolyte temperature at different input currents.
图5. (a) Exfoliation efficiency, (b) graphene yield, (c) XRD patterns, and (d) XPS survey spectra of graphene obtained at different interelectrode distances.
图 6. (a) SEM image and (b) TEM image of graphene nanosheets, (c) AFM images of graphene nanosheets and corresponding histograms of (d) thickness distribution and (e) dimension distribution, (f) oxygen content of graphene measured by an oxygen element analyzer, (g) SEM-mapping of graphene film, (h) Raman spectrum of graphene, and (i) electrical conductivity of graphene film.
图7. Electrolyte temperatures without temperature control in (a) a single-anode electrolyzer and (b) a five-anode array electrolyzer, (c) carbon corrosion of the graphite electrode in the array electrolyzer after establishing stable continuous electrochemical exfoliation, (d) electrolyte temperature and (e) carbon corrosion in the five-anode array electrolyzer after temperature control, (f) reaction rate constants of water decomposition and Na
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generation with increasing reaction temperature, and (g) schematic diagram of the mechanism of exfoliation and carbon corrosion.
图 8. (a) Optical photographs of small- and large-size graphite foils along with size information, (b) carbon corrosion of the small-size graphite foils at different temperatures, SEM images of (c) edge and (d) in-plane surfaces of graphite electrode after exfoliation, and (e) schematic diagram of the mechanism of tip effect on the carbon corrosion.
总之，本文提出了一种灵活的封装策略来制备阳极/阴极电极，并设计了一种阵列电解槽，用于通过电化学剥离法按比例连续安全地生产石墨烯。封装策略有助于提高剥离效率和石墨烯产率，裸阴极/阳极的剥离效率和石墨烯产率分别为 71.5%和 35.5%，封装阴极/阳极的剥离效率和石墨烯产率分别为 98.6%和 39.6%，石墨烯层≤7（97%），C/O 比为 16.9，ID/IG 比为 0.22。此外，剥离产物可被限制在可膨胀过滤袋中，氢气副产物可被限制在离子交换膜中，这两者都确保了放大生产中的连续安全运行。在电化学剥离放大生产过程中，除了通过插层-膨胀-剥离生产石墨烯外，还存在通过水分解途径和 SO42- 氧化途径产生的严重碳腐蚀，这与电解液温度密切相关。在没有电解液冷却的情况下，电解液温度高达 70 ℃，石墨电极的平均碳腐蚀率为 75%。当电解液温度降低到 30 ℃ 以下时，石墨电极的碳腐蚀率大幅下降至约 46.7%。此外，石墨尺寸增大引起的边缘/尖端效应也会造成碳腐蚀。总之，这项工作中的灵活封装策略和阵列电解槽为通过电化学剥离法大规模生产石墨烯提供了一种连续、安全的策略，在进一步的工业应用中显示出巨大的潜力。
文献：
https://doi.org/10.1021/acssuschemeng.4c07558
