Synthesis and characterization of α-MnO2 nanoneedles for electrochemical supercapacitors

In this work, we report the microwave-assisted synthesis of α-MnO2 particles at the aqueous-organic interface. Morphological and structural characterizations were performed by SEM, HR-TEM, RXD and XPS. α-MnO2 particles presented 1D-needle shaped structure with 20 nm thickness. Electrochemical performance was studied by cyclic voltammetry at different potential windows and scan rates, and by galvanostatic charge-discharge measurements. MnO2 nanoneedles exhibited capacitances up to 289 F g−1 (at 0.5 A g−1) and good electrochemical stability (up to 88% of the initial capacitance after 10,000 charge/discharge cycles), confirming a good performance as electrode materials for supercapacitors.