Self-assembled polyoxovanadate-intercalated layered double hydroxide nanosheets hybridized with graphene oxide for extrinsic supercapacitors

초록

Hybrid materials integrate unique organic and inorganic compounds to create innovative materials that harness the optimal characteristics of each component, enhancing the electrochemical performance. Herein, a novel lattice engineering strategy has been established to synthesize self-assembled 2D nickel chromium layered double hydroxide (NC-LDH) nanosheets intercalated with 0D polyoxovanadate (POV) and hybridized with graphene oxide (GO) nanosheets (NCVG). The control of the POV/GO ratio is demonstrated to be crucial in optimizing the layer-by-layer-ordered porous stacking structure and the charge transport behavior, resulting in a remarkable increase in the cycling stability and rate performance of lattice-engineered NCVG nanoarchitecture as compared to NC-LDH. Later, a hybrid supercapacitor device was fabricated using NCVG as the cathode and activated carbon (AC) as the anode. The resulting device (NCVG-2//KOH//AC) delivered a specific energy of 73.8 W h kg-1 at a specific power of 1.06 kW kg-1. The practical feasibility of the device in wearable applications was demonstrated by assembling a hybrid all-solid-state supercapacitor (NCVG-2//PVA-KOH//AC), which achieved an excellent capacitance retention of 92% over 12 000 cycles. This work provides a new opportunity to develop outstanding porous layer-by-layer assembled architectures for the development of efficient materials for energy-oriented applications. POV intercalated LDH hybridized with GO increases basal spacing, forming a porous structure and improving conductivity. This nanoarchitecture, with expanded surface area and abundant redox sites, provides exceptional electrochemical activity.

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