Solid-State Reaction Assisted Synthesis of Co-Doped MnO2 Nano-Composite Materials for Supercapacitor

Electrochemical supercapacitors are charge–storage devices that have greater power density and longer cycle life than batteries, and they possess higher energy density compared with conventional capacitors.  Based on the different operation mechanisms, supercapacitors can be classified into two different categories: double-layer capacitors and pseudocapacitors [1,2].  Recently, relatively cheap oxide alternatives with similar characteristics have been developed to replace ruthenium oxide as electrode materials for use in pseudo-capacitors due to their low cost and no-toxicity.  MnO₂ has been used as one of the promising electrode materials for supercapacitor mainly because of its abundance in nature, low price, environment friendliness, wide charge/discharge potential range and large specific area [3].

In this work, a mechanically assisted solid-state reaction method was employed to prepare Co-doped MnO₂ nanocomposites for supercapacitor electrode materials.  It was found that the specific capacitance of 2.3 wt% Co doped MnO₂ composite electrode was up to 340.1 F g^-1 in 1.0 M KCl solution (Figure 1).  Additionally, as prepared Co doped MnO₂ composite electrode showed other desirable electrochemical properties, including good stable electrochemical properties, excellent reversibility and the long cycle life (Figure 2), demonstrating that it had potential advantages for the fabrication of electrochemical capacitor.

 

References

[1] Wen Lei, Ping He, Susu Zhang, Faqin Dong, Yongjun Ma. One-step triple-phase interfacial synthesis of polyaniline-coated polypyrrole composite and its application as electrode materials for supercapacitors. Journal of Power Sources, 2014, 266: 347-352.

[2] Wen Lei, Ping He, Yuhao Wang, Susu Zhang, Faqin Dong HongTao Liu. Soft template interfacial growth of novel ultralong polypyrrole nanowires for electrochemical energy storage. Electrochimica Acta, 2014, 132: 112-117.

[3] X Lang, A Hirata, T Fujita, M Chen. Nanoporous metal/oxide hybrid electrodes for electrochemical supercapacitors. Nature Nanotechnology, 2011, 6: 232-236.