New Synthesis Method for a Core-Shell Composite Based on α-Bi2O3@PPy and its Electrochemical Behavior as Supercapacitor Electrode

New composite based on polypyrrole (PPy) and bismuth oxide (alpha-Bi2O3) was investigated as supercapacitor electrode. The alpha-Bi2O3 was obtained by hydrothermal route at 500 degrees C for 2 h. Cyclic voltammetry was used to electropolymerize PPy on graphite electrode (GE) or on GE/alpha-Bi2O3. The X-ray diffraction profile of Bi2O3 revealed the alpha-Bi2O3 monoclinic structure with space group P2(1)/c. The scanning and transmission electron microscopy images showed that PPy coated alpha-Bi2O3. Raman spectra showed that PPy inhomogeneously coated alpha-Bi2O3, but it was still possible to obtain a alpha-Bi2O3 OPPy core-shell hybrid composite with highly ordered alpha-Bi2O3 with electronic interaction between the oxide and the polymer chain of the polymer. The GE/alpha-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 alpha-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.