Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (7): 1421-1428.doi: 10.3866/PKU.WHXB201704077

• ARTICLE • Previous Articles     Next Articles

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)

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

MSC2000: 

  • O646