低温加热快速制备膨胀石墨

Rapid preparation of expanded graphite at low temperature

本文提出了一种简单、节能、高效的膨胀石墨制备方法。以鳞片石墨为原料,K2S2O8为膨胀剂,在80℃的条件下,加热数分钟即可快速制备出膨胀石墨。采用XRD、SEM、FTIR、Raman和四探针对样品的结构、形貌、官能团和导电性能进行了表征。结果表明,石墨由鳞片状转变为蠕虫状,最大膨胀容积为150 mL/g,且该方法对石墨结构的氧化程度低。由该膨胀石墨制备的柔性石墨的电导率为5.47×104S/m。该方法因其简单、成本低、对环境危害小等特点具有良好的应用前景。

The traditional methods for preparing expanded graphite(EG)often require harsh conditions and take a long time resulting in a high-cost and severe environmental pollution.A simple,energy-saving and efficient route for preparing EG was developed,in which flake graphite was exfoliated with K2S2O8under concentrated H2SO4at 80℃for a few minutes.The microstructures,morphology and functional groups of the EG were characterized by XRD,SEM,FT-IR and Raman spectroscopy,and the electrical conductivity was measured by a four-point probe method.Results indicated that the flake graphite transformed into a wormlike structure after expansion with slight damage to the graphite sheets.A maximum expanded volume of 150 mL/g was obtained under the optimal conditions of 80℃for 5 min with mass ratios of graphite to K2S2O8of 1∶7 and graphite to concentrated H2SO4of1∶20.The electrical conductivity of the flexible graphite film prepared by rolling from the optimized EG reached 5.47×104S/m.The mild oxidation and oxygen released by the decomposition of K2S2O8under the acidic conditions are responsible for the efficiency of the method,which is promising for the mass production of EG due to its simplicity,low cost and low environmental impact.