Construction of core-shell heterostructure containing sandwich-like nanoarray for high-performance supercapacitors

Abstract

Designing and constructing an ideal architecture is an effective approach to realize high-performance energy storage system. Core-shell heterostructure materials have attracted much attention due to their excellent performance in energy storage applications. Whereas, core-shell heterostructure containing sandwich-like nanoarray materials have rarely been reported by far. Herein, sandwich-like NiCo-PPy-layered double hydroxide (NiCo-PPy-LDH) nanosheets with polypyrrole (PPy) as the intercalation agent were vertically anchored on 3D cross-linked graphene nanoscroll (GNS) skeleton via a hydrothermal method and subsequent in situ polymerization process. Impressively, the as-prepared NiCo-PPy-LDH@GNS composite delivers a prominent specific capacitance of 2561 F·g−1 (equivalent conversion to 1024.4C·g−1) at 1 A·g−1 with 82 % capacitance retention at 10 A·g−1. The superior electrochemical properties of the NiCo-PPy-LDH@GNS is mainly attributed to its novel heterostructure which enhances the synergistic effect between NiCo-LDHs, GNSs, and PPy. The intercalation of PPy enriches hetero-interface and active sites for the redox reaction, while the GNSs skeleton provides a 3D rigid conductive network for further enhancing charge transportation and preventing the aggregation of LDH nanosheets.