Facile synthesis of MnO2/polyaniline nanorod arrays based on graphene and its electrochemical performance

• The graphene/MnO2/PANI ternary nanocomposite was fabricated via simple electrochemical method.
• Highly ordered MnO2/PANI nanorod arrays were obtained on graphene film.
• Graphene/MnO2/PANI exhibited high specific capacitance and excellent cycling stability.
• Graphene induced morphological variations.
• Possible mechanism for the effect of graphene on the morphology of MnO2 and electrochemical performance was proposed.

In order to overcome the poor stability of polyaniline (PANI) and to improve the electrochemical performance based on graphene, MnO2 and PANI ternary composite, graphene/MnO2/PANI nanorod arrays (GMPNAs) were fabricated firstly via synthesizing highly ordered MnO2/PANI coaxial nanorod arrays on graphene film, using a simple and controllable electrochemical technique. With the arrays structure and synergetic interaction between graphene, MnO2, and PANI, which not only can provide high interfacial area, short ion diffusion path, and fast electrical pathways, but also can reduce agglomeration of material in using process, the specific capacitance and cycling stability of GMPNAs were improved greatly compared to that of pure PANI and MnO2/PANI binary composite. The maximum specific capacitance of GMPNAs was as high as 755 F g−1 at a current density of 0.5 A g−1 and retained 87% of the initial capacitance after 1000 cycles. It is believed that the GMPNAs composite will have a great potential for application in supercapacitors and the design of microstructure of GMPNAs is extendable to other pseudocapacitive electrodes.