Fabrication of self-supporting electrode by integrating Ni-Co-Al layered double hydroxides on graphene aerogel scaffold for high-performance asymmetric supercapacitors

초록

Supercapacitors are among the most promising energy storage devices due to their high power density and long-term cycling stability. However, conventional electrode fabrication, which relies on binder-containing slurries and metallic current collectors, introduces inactive components and increased internal resistance, thereby limiting overall device performance. Herein, we report a self-supporting nickel-cobalt-aluminum layered double hydroxide/graphene aerogel (NCA-LDH/GA) electrode fabricated via a film-casting–electrodeposition strategy. The GA, consisting of an interconnected three-dimensional (3D) porous graphene network, enables rapid electron transport and efficient electrolyte ion diffusion. Moreover, the residual oxygen-containing functional groups from GA facilitate the uniform nucleation and strong interfacial interaction of LDH nanosheets, thereby enhancing electrochemical performance. The resulting electrode can be directly used without the need for external metallic current collectors or binders. This NCA-LDH/GA electrode delivers a high specific capacitance of 2410 F g−1 at 1 A g−1 and retains 88% of its initial capacitance after 5000 charge–discharge cycles. Furthermore, a fully self-supported asymmetric supercapacitor (ASC) assembled using GA-based electrodes (NCA-LDH/GA//GA) achieves a high energy density of 50.6 Wh kg−1 at 817 W kg−1 and retains 92% of its initial capacitance after 10,000 cycles and 87.6% after 20,000 cycles, demonstrating excellent cycling stability. Notably, the fabrication approach employs a casting process, which is suitable for scalable electrode fabrication, while the ultralight GA framework further enables lightweight energy storage devices.

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