New synthesis method for a core-shell composite based on ?-Bi2O3@PPy and its electrochemical behavior as supercapacitor electrode.

New composite based on polypyrrole (PPy) and bismuth oxide (?-Bi2O3) was investigated as supercapacitor electrode. The ?-Bi2O3 was obtained by hydrothermal route at 500 ?C for 2 h. Cyclic voltammetry was used to electropolymerize PPy on graphite electrode (GE) or on GE/?-Bi2O3. The X-ray diffraction profile of Bi2O3 revealed the ?-Bi2O3 monoclinic structure with space group P21/c. The scanning and transmission electron microscopy images showed that PPy coated ?-Bi2O3. Raman spectra showed that PPy inhomogeneously coated ?-Bi2O3, but it was still possible to obtain a ?-Bi2O3@PPy core-shell hybrid composite with highly ordered ?-Bi2O3 with electronic interaction between the oxide and the polymer chain of the polymer. The GE/?-Bi2O3@PPy composite electrode (type I supercapacitor) displayed a predominantly capacitive profile with low impedance values and good electrochemical stability after 50 charge and discharge cycles. The specific capacitance of ?-Bi2O3@PPy composite was found in the range of 634 to 301 F g-1 to gravimetric current of 3 and 10 A g-1, respectively