Preparation and electrochemical properties of CPAC/Mn3O4 nanocomposite electrode

He-Ming Luo,Feng-Bo Zhang,Peng Yang

doi:10.1007/s10854-012-0992-2

Abstract

Novel nanocomposite electrode, coke powder activated carbon/Mn3O4 (CPAC/Mn3O4), was prepared by Sol–Gel method using CPAC/Mn(OH)2 as a precursor. The CPAC/Mn3O4 was characterized by field emission scanning electron microscopy and X-ray diffraction (XRD). The results show that the composite electrode material has a nano-rod structure and Mn3O4 is in mixed phase composed of MnO and MnO2. The influence factors on the electrochemical performance of electrode materials including manganese content of the precursor, different calcining temperature and time of the precursor were investigated. The results obtained from electrochemical measurement show that the electrode possesses better electrochemical performance with a manganese content of 20 wt % in precursor. In addition, the specific capacitance of CPAC/Mn3O4 nanocomposite electrode material could reach up to 277 F g−1 at a calcining temperature of 500 °C and a calcining time of 3 h, respectively.

Highlights

Supercapacitor has been considered as a new extremely valuable energy storage device, because of its excellent functions such as fast charging and discharging, high power, fairly high energy density, long cycle life, and friendly to environment [1–3]
Nano-rods composite material of Coke powder activated carbons (CPACs)/Mn3O4 was prevalently easy to be touched or attached by the active substances and the ions in electrolyte, which facilitate to the H? or OH- removing from the pore channel of nanocomposite material, produced by reaction and prompted to evacuate
We found that the specific capacitance of nanocomposite electrode materials is lower than that of the CPAC samples itself (211 F g-1) with a calcining time of 2 h

Summary

Introduction

Supercapacitor has been considered as a new extremely valuable energy storage device, because of its excellent functions such as fast charging and discharging, high power, fairly high energy density, long cycle life, and friendly to environment [1–3]. Owing to different crystal structure of manganese oxide, they often exhibit different electrochemical properties, among which c-MnO2 shows a relatively high electrochemical active property [9, 10]. Reports of manganese oxide used as electrode materials are mainly focused on c-MnO2 and a-MnO2 [11–14]. The coke powder prepared by alkali activation has mainly been used in the wastewater treatment but seldom involved in electrode materials [15]. Coke powder activated carbon and CPAC/Mn3O4 composite electrode material were prepared in a continuation of our pervious study [16]. The electrochemical performance of CPAC/Mn3O4 electrode materials, which was prepared under the conditions of different calcining temperature and time, were systematically investigated. The prepared composite electrode materials was performed under the protection of N2, and calcined at different temperature (300, 400, 500 and 600 °C) for 2, 3, and 4 h respectively. Pressed at 10 MPa for 1–2 min, and dried in vacuum for 4 h

Characterization and electrochemical measurement

FESEM analysis

Chronopotentiometry

Cyclic voltammetry

Conclusions