Core-shell nanospherical polypyrrole/graphene oxide composites for high performance supercapacitors

摘要

Novel core-shell polypyrrole/graphene oxide (PPy-GO) nanomaterials of uniform PPy nanospheres and GO have been synthesized by an in situ surface-initiated polymerization method. The morphology and structure of the core-shell PPy-GO composites were studied by means of techniques. Experimental results showed that PPy nanospheres with small nanospheres of only ～70 nm were uniformly grown on the GO sheets to form continuous 3D core-shell PPy-GO nanocomposites. The smaller size of PPy can not only be more beneficial to increasing the electrochemical performance, but can also reduce the ion diffusion path and make it a higher material for utilization. Moreover, the well-designed core-shell nanostructure and synergistic effects of PPy-GO composites can clearly lead to high rates of electrode reaction and good electrode/electrolyte contact areas. Meanwhile, its electrochemical performance was evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) tests. The specific capacitance of the core-shell PPy-GO nanocomposites can reach up to 370 F g~(-1) at a current density of 0.5 A g~(-1) with a large mass loading of 8.0 mg cm~(-2) . It is noteworthy that the cycling stability of the PPy-GO electrode was improved significantly by the core-shell nanostructures, and showed excellent capacitance retention (91.2%) even after 4000 cycles, suggesting its attractive application in supercapacitors with improved performance.