An ultra-high energy density flexible asymmetric supercapacitor based on hierarchical fabric decorated with 2D bimetallic oxide nanosheets and MOF-derived porous carbon polyhedra

摘要: Flexible supercapacitors (SCs) are an emergent and promising technology for next-generation energy storage devices. However, low densities hindered their practical applications. Two-dimensional (2D) nanosheets can exhibit excellent electrochemical charge properties due to short ion-diffusion distance rich electroactive sites with multiple valence states. Herein, we report the direct growth of mesoporous 2D zinc cobaltite on a flexible carbon cloth substrate (Zn–Co–O@CC) average thickness ∼45 nm by facile hydrothermal method at temperature. The Zn–Co–O@CC electrode displays high capacitance 1750, 1573.65 1434.37 F g−1 current density 1.5 A in LiCl, NaCl KCl neutral aqueous electrolytes, respectively, rate capabilities demonstrates good cycling stability (>94%) up 5000 cycles. Moreover, highly asymmetric supercapacitor (ASC) devices have been fabricated using as positive bimetallic organic framework (MOF)-derived nanoporous polyhedra (NPC@CC) negative (Zn–Co–O@CC//NPC@CC). as-fabricated ASC operate large potential window 0.0–2.0 V shows outstanding performance delivering ultra-high 117.92 W h kg−1 power 1490.4 94% after charge/discharge To best our knowledge, achieved device is very competitive highest among all binary metal oxides, carbonaceous materials, MXene-based SCs ASCs date. applied strategy fabricate capable enhancing both activity stability, be readily other oxide-based SCs.