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以尿素、四水合氯化锰和氧化石墨烯为原料,采用水热法并通过热分解制备了一种具有石墨烯包覆结构的石墨烯-二氧化锰复合材料,利用扫描电子显微镜、X射线衍射、比表面积(BET)、拉曼光谱和热失重等技术对其形貌、晶体结构及表面结构进行了表征;在三电极条件下利用循环伏安法、恒流充放电法和交流阻抗法测试了材料的电化学性能,并考察了不同石墨烯含量对材料比电容的影响.结果表明,在不添加模板剂的条件下制备的复合材料中二氧化锰是具有介孔结构的α-MnO2,当复合15%(质量分数)的石墨烯后材料的比表面积从109 m2·g-1提高到168 m2·g-1.复合材料具有更好的电化学性能,在0.2 A·g-1电流密度下复合材料的比电容达到最大值(454 F·g-1),远高于纯二氧化锰的值(294 F·g-1).在2 A·g-1的电流密度下恒流充放电2000次后复合材料的比电容保持率为92%.
A series of graphene-manganese dioxide composites with graphene-coated structure were prepared by hydrothermal method using urea, manganese chloride tetrahydrate, and graphene oxide as graphene oxides. Scanning electron microscopy (SEM), X-ray Its morphology, crystal structure and surface structure were characterized by X-ray diffraction, BET, Raman spectroscopy and thermogravimetry. Cyclic voltammetry, constant current charge-discharge method and AC impedance method The electrochemical performance of the material was tested and the effect of different graphene content on the specific capacitance of the material was investigated.The results showed that the manganese dioxide in the composite prepared without adding the template agent is a mesoporous structure of α-MnO2 , And the specific surface area of the composites increased from 109 m2 · g-1 to 168 m2 · g-1 when 15% (mass fraction) of the composite was composited. The composite had better electrochemical performance, The maximum specific capacitance of the composites at current density (454 F · g-1) was much higher than that of pure manganese dioxide (294 F · g-1). At constant current density of 2 A · g -1 After 2000 charge / discharge cycles, the specific capacitance of the composite was 92%.