Hollow 1D carbon tube core anchored in Co₃O₄@SnS₂ multiple shells for constructing binder-free electrodes of flexible supercapacitors

The design of the core@multi-shell metal sulfide hollow tube is of great importance for various supercapacitor electrodes. Herein, a hollow carbon tube (HCT) core@multi-shell with rich pores is developed for constructing the binder-free flexible electrodes (HCT-x@Co₃O₄@SnS₂). The inner core–shell is derived from the zeolitic imidazole framework (ZIF)-8@ZIF-67 porous carbon tube and is engineered with vertically aligned SnS₂ nanosheets. The unique inner core–shell and the outer-shell SnS₂ contribute to the excellent characteristics, including abundant pores and channels for the rapid ion transport and storage, high specific surface area, improved electrical conductivity, and additional electroactive sites for the faradaic reaction. Thanks to the synergies between the unique 1D porous hollow structure and the different components, the as-fabricated HCT-2@Co₃O₄@SnS₂ electrode exhibits a high specific capacitance of 439 F/g at 1 A/g. Moreover, the assembled flexible supercapacitor also demonstrates a remarkable energy density of 40.22 Wh kg⁻¹, the corresponding power densities of 750.22 W kg⁻¹, and long cycle life. In addition, no structural deformation and capacitance loss are observed in the bended devices. The developed approach provides a facile structure design route for the flexible binder-free electrode preparation of flexible energy storage applications.