热剥离温度对石墨烯结构及电性能的影响

Influence of Thermal Exfoliation Temperature on Structure and Capacitance Properties of Graphene

以天然石墨为原料,采用Hummers法制备氧化石墨（GO）,再在200～700℃进行热还原,制备石墨烯.采用SEM、XRD和比表面积仪测试分析样品的微观结构和比表面积;并用恒流充放电测试仪测试样品的电容性能.研究表明：所得石墨烯具有片层结构,层间距为0.3783～0.3873nm,晶粒大小为2.030～3.359nm,层数均为5～9层;随着热还原温度的升高,石墨烯的层间距、晶粒大小和层数均逐渐减小,而比表面积逐渐增大.随着温度的升高,比电容先升高后降低,循环性能一直增加,400℃热还原的石墨烯首次放电比电容为318.6F/g,经过500次循环后容量保持率为54％.

The graphene was obtained from flake graphite by Hummers method and a subsequent thermal exfo- liation and reduction at 200-700 ℃. The microstructure and specific surface area of the sample were analyzed using SEM, XRD and specific surface area test. The capacitive performance was tested by constant current charge-discharge set. The results shows： graphene has layered structure, the layer spacing of graphene is about 0. 3783-0. 3873 nrn, the grain size of graphene is about 2. 030-3. 359 nm, the number of layers is 5-9. With the increase of thermal re- duction temperature, the layer spacing of graphene, the grain size of graphene and the number of layers are gradually reduced, and the specific surface area of graphene rises gradually. With the increase of temperature, specific capaci- tance of graphene increases first and then decreases, and cyclic performance increases--the initial discharge specific ca- pacitance of the graphene is 318. 6 F/g when thermal reduction temperature is 400 ℃ and the capacity remain is about 54% after 500 cycles.