Hydrothermal regulation of hierarchical Al-doped nickel-cobalt layered double hydroxide nanoneedle arrays for hybrid supercapacitors

Abstract

Nickel-cobalt-based (NiCo) supercapacitors have garnered widespread attention owing to their high rate performance, safety, and low cost. However, conventional NiCo-layered double hydroxide (LDH) materials often exhibit low electrical conductivity, structural instability, and a limited number of exposed active sites. To address these issues, a reaction-time-controlled hydrothermal strategy was utilized to regulate the growth of an aluminum-doped nickel-cobalt LDH, enabling the formation of flower-like microstructures composed of interconnected nanoneedle arrays with improved ion-transport pathways and electrochemical performance. Notably, Al doping expanded the interlayer spacing, which facilitated rapid ion diffusion and improved the rate capability and charge-discharge efficiency. The electrochemical performance of the assembled device, including energy density, powerdensity, and cycling stability, was systematically studied. Moreover, device-level optimization was achieved using strategies to widen the operating voltage window in asymmetric supercapacitors. The feasibility of the device was further supported by powering a light-emitting diode, electronic watch, calculator, and small electric fan, confirming its stable output performance.

Keywords

Nickel-cobalt-aluminum LDH / hydrothermal synthesis / interlayer spacing / hierarchical nanostructures / hybrid supercapacitors

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Higher Education Press 2027

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