Design of an Internal/External Bicontinuous Conductive Network for High Performance Asymmetrical Supercapacitors

Abstract

High energy density supercapacitors have attracted extensive attention due to their electrode structure design. In this work, the distinctive PPy@FeNi 2 S 4 @NF and PPy@NiCo 2 S 4 @NF material are prepared by a simple two-step hydrothermal synthesis with subsequent in situ polymerization method. Synergistic effect related to core-shell structure can improve the energy storage capacity and power density of electrode materials. While Ni-foam(NF) substrate coupled with polypyrrole (PPy) conductive coating can serve as an internal/external bicontinuous conductive network. The PPy@FeNi 2 S 4 @NF and PPy@NiCo 2 S 4 @NF could deliver ultrahigh specific capacitance of 3908.5 F·g -1 and 5142.8 F·g -1 at 1 A·g -1 , marvelous cycling capability performance of 81.39% and 93.02% after 5000 cycles. The asymmetric supercapacitors composed of the prepared materials provide a high energy density over 47.2 Wh·kg -1 at 699.9 W·kg -1 power density and 67.11 Wh·kg -1 at 800 W·kg -1 power density. Therefore, the as-constructed self-assembled core-shell structure was a notable efficient profile for supercapacitors candidate and will have an effectively serving in flexible advanced energy storage devices.

Keywords: Ni-based bimetallic sulfide, Core-shell structure, Bicontinuous conductive network, Polypyrrole coating, Asymmetric supercapacitors