Fe3O4@PPy@MnO2 ternary core-shell nanospheres as electrodes for enhanced energy storage performance

The rapid development of supercapacitors has led to increasing demand for electrode materials with excellent electrochemical properties. In this study, Fe3O4@PPy@MnO2 nanocomposites with porous core and double-shell layers were successfully synthesized and utilized as supercapacitor electrode materials. Specifically, a dense PPy coating is formed on the porous Fe3O4 surface to ensure high structural stability, and a MnO2 shell layer could be easily introduced on the PPy surface through the redox reaction between PPy and KMnO4. The prepared composite electrode material has the advantages of high specific surface area, short diffusion distance of electrolyte ions, good electron transfer, and fast and reversible Faraday reaction. The Fe3O4@PPy@MnO2 electrode not only exhibits high specific capacitance (751F g(-1) at 1 A/g), but also exhibits excellent cycling stability (87.0 % capacitance retention after 5000 cycles at 4 A/g). This is owing to the synergistic effect of the porous Fe3O4 core, the dense PPy coating, and the MnO2 nanosheet shell. Furthermore, the asymmetric supercapacitor devices assembled with Fe3O4@PPy@MnO2 nanocomosite possess remarkable cycling stability (95.2 % after 5000 cycles at 5 A/g) and high energy density (71.3 Wh kg(-1) at the power density of 750 W kg(-1)). These results demonstrate the great potential of Fe3O4@PPy@MnO2 nanocomposites with porous cores and double shells as electrode materials for high-performance supercapacitors.

Automated summary

This study successfully synthesized Fe3O4@PPy@MnO2 nanocomposites with porous core and double-shell layers, and utilized them as supercapacitor electrode materials. The prepared composite electrode material showed high specific capacitance and excellent cycling stability, demonstrating great potential for high-performance supercapacitors.