物理化学学报 >> 2017, Vol. 33 >> Issue (7): 1421-1428.doi: 10.3866/PKU.WHXB201704077

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α-MnO2纳米管自组装微球的可控制备及电化学性能

鞠广凯,陶占良*(),陈军   

  • 收稿日期:2017-03-01 发布日期:2017-05-31
  • 通讯作者: 陶占良 E-mail:taozhl@nankai.edu.cn
  • 基金资助:
    国家重点研发计划(2016YFB0901502);国家自然科学基金(21231005);国家自然科学基金(51371100)

Controllable Preparation and Electrochemical Performance of Self-assembled Microspheres of α-MnO2 Nanotubes

Guang-Kai JU,Zhan-Liang TAO*(),Jun CHEN   

  • Received:2017-03-01 Published:2017-05-31
  • Contact: Zhan-Liang TAO E-mail:taozhl@nankai.edu.cn
  • Supported by:
    the National Key R&D Program of China(2016YFB0901502);the National Natural Science Foundation of China(21231005);the National Natural Science Foundation of China(51371100)

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摘要：

以KMnO4、HCl为反应物，H2SO4、NH4Cl为助剂，利用水热法成功合成了α-MnO2纳米管自组装微球。并采用X射线晶体衍射（XRD）、场发射扫描电子显微镜（SEM）、透射电子显微镜（TEM）以及X射线光电子能谱（XPS）表征手段对产物进行了形貌和结构表征，发现H+与Cl-离子浓度对产物的晶型有很大影响：单一增加H+或Cl-离子浓度可以使纳米管管径减小、长度增加；同时增加两种离子浓度则产物从α相转化为β相；NH4+可以起到维持产物晶型（α相）以及管状形貌的作用。电化学性能测试表明，具有独特形态的α-MnO2纳米管微球作为锂电负极具有高容量（20 mA·g-1电流密度下首周放电比容量达1783.5 mAh·g-1）与良好的倍率性能，是具有广阔应用前景的锂离子电池材料。

关键词: α-MnO2纳米管, 可控制备, 自组装微球, 水热合成法, 锂离子电池

Abstract:

Self-assembled microspheres of α-MnO2 nanotubes were successfully synthesized by hydrothermal method using KMnO4 and HCl as reactants, and H2SO4 and NH4Cl as auxiliaries. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the products. The H+ and Cl- ion concentrations substantially influence the crystal form of the product. Increasing either H+ or Cl- ion concentration decreases the diameter of nanotubes but increases their length. In contrast, increasing both H+ and Cl- ion concentrations, changes the product from α phase to β phase. Moreover, NH4+ ion plays the key role of maintaining the product crystal and its tubular morphology. The electrochemical performance results showed that the microspheres of α-MnO2 nanotubes with a unique morphology have a high first cycle discharge capacity of 1783.5 mAh·g-1 at the current density of 20 mA·g-1, along with a good rate performance. This suggests that the self-assembled microspheres were a promising material for lithium-ion batteries.

Key words: α-MnO2 nanotubes, Controllable preparation, Self-assembled microspheres, Hydrothermal synthesis, Lithium-ion battery