Hybrid supercapacitors (HSCs) have aroused considerable attention by virtue of their high ionic conductivity and operation voltage. In this study, three-dimensional (3D) flower-like hierarchical NiCo layered double hydroxide (LDH) microspheres are synthesized via a simple and gentle alkaline hydrolysis strategy. Compared with MOF precursors, the obtained NiCo-LDH microspheres could maintain their initial morphology and possess a more uniform pore structure with a higher specific surface area which are suitable for supercapacitors. By regulating the alkali concentration, it is found that an optimal electrochemical performance is obtained with high specific capacitance (1750.0 F g⁻¹ at 1 A g⁻¹) and superior cycling durability (retaining 91.0% after 3000 cycles) when the alkaline concentration is 1 mol L⁻¹. Subsequently, NiCo-LDH//AC HSC assembled by combining NiCo-LDH with activated carbon (AC) achieves a maximum energy density of 48.6 W h kg⁻¹ when the power density is 850 W kg⁻¹ and equipped with remarkable cycle durability (maintaining 92.3% after 5000 cycles). These incredible electrochemical properties are mainly ascribed to the exceptional hierarchical structure, porosity and specific surface area, contributing to facilitate the rapid transmission of electrons and ions. The alkali hydrolysis strategy provides a new choice for the preparation of high-efficiency electrode materials and the design of hybrid supercapacitors.

中文翻译：

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用于混合超级电容器的具有增强电化学性能的 3D 花状分层 NiCo-LDH 微球的合成

混合超级电容器（HSC）由于其高离子电导率和工作电压而引起了广泛关注。在这项研究中，通过简单温和的碱水解策略合成了三维（3D）花状分层镍钴层状双氢氧化物（LDH）微球。与 MOF 前驱体相比，所获得的 NiCo-LDH 微球可以保持其初始形态，并具有更均匀的孔结构和更高的比表面积，适用于超级电容器。通过调节碱浓度，发现具有高比电容（1750.0 F g ^-1 at 1 A g ^-1) 和优异的循环耐久性（3000 次循环后保持 91.0%），当碱浓度为 1 mol L ^{-1 时}。随后，由NiCo-LDH与活性炭（AC）结合组装而成的NiCo-LDH//AC HSC在功率密度为850 W kg ^-1时达到了48.6 W h kg ^-1的最大能量密度，并具有显着的循环耐久性（ 5000 次循环后保持 92.3%）。这些令人难以置信的电化学性能主要归因于特殊的分级结构、孔隙率和比表面积，有助于促进电子和离子的快速传输。碱水解策略为高效电极材料的制备和混合超级电容器的设计提供了新的选择。