物理化学学报 >> 2013, Vol. 29 >> Issue (08): 1681-1690.doi: 10.3866/PKU.WHXB201305223

电化学和新能源 上一篇    下一篇

水热合成部分还原氧化石墨烯-K2Mn4O8超级电容器纳米复合材料

李乐1, 贺蕴秋1,2, 储晓菲1, 李一鸣1, 孙芳芳1, 黄河洲1   

  1. 1 同济大学材料科学与工程学院, 上海 200092;
    2 同济大学先进土木工程材料教育部重点实验室, 上海 200092
  • 收稿日期:2013-02-27 修回日期:2013-05-21 发布日期:2013-07-09
  • 通讯作者: 贺蕴秋 E-mail:heyunqiu@tongji.edu.cn
  • 基金资助:

    国家自然科学基金(51175162)资助项目

Hydrothermal Synthesis of Partially Reduced Graphene Oxide-K2Mn4O8 Nanocomposites as Supercapacitors

LI Le1, HE Yun-Qiu1,2, CHU Xiao-Fei1, LI Yi-Ming1, SUN Fang-Fang1, HUANG He-Zhou1   

  1. 1 School of Material Science and Engineering, Tongji University, Shanghai 200092, P. R. China;
    2 Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Tongji University, Shanghai 200092, P. R. China
  • Received:2013-02-27 Revised:2013-05-21 Published:2013-07-09
  • Contact: HE Yun-Qiu E-mail:heyunqiu@tongji.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51175162).

摘要:

通过控制水热反应温度以及氧化石墨烯(GO)与高锰酸钾的填料比, 合成了两组部分还原的GO-K2Mn4O8纳米复合材料. X射线衍射(XRD)分析说明水热过程中合成了α-MnO2和一种新的晶相K2Mn4O8.通过X射线光电子能谱(XPS)分析了水热反应前后氧化石墨的含氧官能团的变化. 扫描电子显微镜(SEM)显示样品由片状还原的氧化石墨烯构成, 其表面附有许多小的纳米颗粒, 这种结构有利于储能时电子的传递. 通过这两组复合材料的结构分析, 更好地理解了材料的电化学性能的变化. 利用循环伏安法和恒流充放电测试比较了材料的电容性能. 用1 mol·L-1的硫酸钠做电解液, 电位范围是0-1 V, 在1 A·g-1的电流密度下, 测得的样品最佳比电容达到251 F·g-1, 能量密度为32 Wh·kg-1, 功率密度为18.2 kW·kg-1. 并且在5 A·g-1的电流密度下循环1000次后样品的比电容仍维持在初始比电容的88%.

关键词: 超级电容器, 还原的氧化石墨烯, 钾锰氧化物, 氧化锰, 复合材料, 电容性能

Abstract:

Nanocomposites of partially reduced graphene oxide (GO)-K2Mn4O8 were synthesized via a hydrothermal process at different temperatures and molar feed ratios of GO to KMnO4. X-ray diffraction (XRD) analysis confirmed that both α-MnO2 and a novel crystal phase of K2Mn4O8 were obtained under the investigated hydrothermal conditions. X-ray photoelectron spectroscopy (XPS) revealed diverse changes of the oxygen-containing functional groups on the surface of GO depending on temperature and molar feed ratio. The microstructure of the composites was studied to help understand their electrochemical properties. A flaky structure of reduced graphene oxide (rGO) covered by nanoparticles was observed by scanning electron microscope (SEM), which was considered to be favorable for charge transfer. The capacitive properties of the composites were compared using cyclic voltammograms and galvanostatic charge-discharge measurements. The specific capacitance of the optimal sample was calculated to be 251 F·g-1 with an energy density of 32 Wh·kg-1 and a power density of 18.2 kW·kg-1 in 1 mol·L-1 Na2SO4 electrolyte at a current density of 1 A·g-1 between 0 and 1 V. Moreover, the capacitance retention ratio of this sample remained at 88% after 1000 cycles at a high current density of 5 A·g-1.

Key words: Supercapacitor, Reduced graphene oxide, Potassium manganese oxide, Manganese oxide, Composite, Capacitive behavior

MSC2000: 

  • O646