Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (4): 693-699.doi: 10.3866/PKU.WHXB201502021

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Hydrothermal Synthesis of Al-Doped α-MnO2 Nanotubes and Their Electrochemical Performance for Supercapacitors

LI Yang, XIE Hua-Qing, LI Jing   

  1. School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209, P. R. China
  • Received:2014-09-09 Revised:2015-01-29 Published:2015-04-03
  • Contact: LI Yang E-mail:liyang@sspu.edu.cn
  • Supported by:

    The project was supported by the Key Innovation Foundation of Shanghai Education Commission, China (13ZZ139), Key Discipline Construction (Materials Science) of Shanghai Second Polytechnic University, China (XXKPY1302), and Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, China.

Abstract:

α-MnO2 and Al-doped α-MnO2 were synthesized via a hydrothermal method. The morphologies, structures, and electrochemical performances of as-synthesized un-doped and doped α-MnO2 were studied. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) show that these un-doped and doped α-MnO2 are nanotube shaped. The band gaps of α-MnO2 are investigated by ultraviolet-visible absorption spectroscopy, which indicates that the band gap of α-MnO2 decreases upon Al doping. The electrochemical performances of un-doped and doped α-MnO2 as electrode materials for supercapacitors were measured by cyclic voltammetry (CV) and galvanostatical charge/discharge tests. The specific capacitances of un-doped and Al-doped α-MnO2 respectively reach 204.8 and 228.8 F·g-1under a current density of 50 mA·g-1. It was discovered that the electrochemical impedance of Al-doped α-MnO2 was decreased by Al doping analyzed using electrochemical impedance spectra (EIS), which provides a beneficial increase to its electrochemical specific capacitance. Enhanced specific capacitance and preferable cycling stability (up to 1000 cycles) for Al-doped α-MnO2 mean that these systems are favorable prospects for application in supercapacitors.

Key words: α-MnO2, Al doping, Nanotube, Supercapacitor, Electrochemical capacitor

MSC2000: 

  • O646