Significant efforts have been directed towards the preparation and application of porous hierarchically structured materials owing to their large surface area, rich active sites, and enhanced mass transport and diffusion. In this study, a simple and cost-effective method for the carbon quantum dot (CQD)-induced assembly of two-dimensional ultrathin Ni(OH)₂ nanosheets into a three-dimensional (3D) porous hierarchical structure was developed. The electrostatic forces between the CQDs and cations drove the self-assembly of the 3D CQDs/Ni(OH)₂ hierarchical structures. As a new type of structure-directing agent, the CQDs played dual roles in tuning the morphology of the products and improving the supercapacitor performance. The multilevel CQDs/Ni(OH)₂ micro-nanostructures had a large specific surface area and rich porosity. Owing to their unique structures and the conductivity of the CQDs, an optimized asymmetric supercapacitor using the CQDs/Ni(OH)₂ exhibited a maximum specific capacity of 161.3 F·g^–1 and a high energy density of 57.4 Wh·kg^–1. This study introduces a potential method for the fabrication of many other 3D hierarchical structures with great potential for applications in various fields.

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由于其大的表面积，丰富的活性位点以及增强的质量传输和扩散，已经对多孔分级结构材料的制备和应用进行了重大努力。在这项研究中，开发了一种简单且经济高效的方法，用于将碳量子点（CQD）诱导的二维超薄Ni（OH）₂纳米片组装为三维（3D）多孔层次结构。CQD和阳离子之间的静电力驱动3D CQD / Ni（OH）₂层次结构的自组装。作为一种新型的结构导向剂，CQD在调整产品的形态和改善超级电容器性能方面起着双重作用。多级CQD / Ni（OH）₂微纳米结构具有大的比表面积和丰富的孔隙率。由于其独特的结构和CQD的电导率，使用CQD / Ni（OH）₂的优化不对称超级电容器表现出最大比容量161.3 F·g ^–1和高能量密度57.4 Wh·kg ^–1。这项研究介绍了一种潜在的方法，用于制造许多其他3D层次结构，具有在各个领域中应用的巨大潜力。

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