Multicore-shell MnO2@Ppy@N-doped porous carbon nanofiber ternary composites as electrode materials for high-performance supercapacitors.

[Display omitted] • A simple hydrothermal synthesis reaction was used to prepare the ternary composite electrode material with multicore-shell. • A large number of flower-like nanospherical δ-MnO 2 were grown on the outermost layer. • Using the control variable method and the Box-Behnken experimental design model in RSM. • The effects of reaction parameters on the growth of MnO 2 were discussed in detail. In this study, a multicore-shell ternary composite electrode material (MnO 2 @Ppy@NPCNFs) with excellent electrochemical performances was prepared by using surface modification, in which core–shell Ppy@N-doped porous carbon nanofibers (Ppy@NPCNFs) with large specific surface area and high conductivity were used as the substrate (a multicore layer), and MnO 2 was loaded on the substrate by hydrothermal synthesis to form a shell layer, further improving the SC of electrode material. The parameters of hydrothermal growth of MnO 2 on Ppy@NPCNFs were explored by means of the control variable method and response surface methodology, and the optimal parameters were predicted and verified. Electrochemical test results showed that the SC of MnO 2 @Ppy@NPCNFs prepared under the optimal reaction parameters was as high as 595.77 F g−1, and its capacitance retention was 96.2 % after 1000 cycles. Moreover, a symmetric supercapacitor prepared with the optimal multicore-shell electrode showed an energy density of 9.36 Wh kg−1 at a power density of 1000 W kg−1 and a retention rate of 92.46 % after 1000 cycles, indicating the promising application of multicore-shell ternary composite electrode material in high-performance supercapacitors. [ABSTRACT FROM AUTHOR]