Abstract The properties of electrode materials are greatly determined by their structures including surface area, pore size distribution and conductivity. Aiming for the advanced structure, we successfully design and develop a core-shell nanocomposite of polydopamine based N-doped carbon spheres (NCSs) and CoxNi1-x(OH)2 by a fast and simple two-step method. Firstly, regular NCSs are directly derived from carbonization of polydopamine, which offer conductive cores for fast electronic transport. Then, flower-like shells consisting of interlinked CoxNi1-x(OH)2 ultrathin nanosheets are vertically and evenly grafted on the surface of NCSs substrate by a chemical bath deposition method, which is faster and more suitable for large-scale production than hydrothermal synthesis. To get the homogeneous bimetal hydroxides CoxNi1-x(OH)2 through this rapid precipitation process, the influences of Co doping content on the morphologies, structure and capacitance properties of hybrids are further analyzed. Results show that the obtained NCSs@CoxNi1-x(OH)2 nanocomposite with small amount of Co doping exhibits impressively enhanced specific capacitance (2065 F g−1 at 1 A g−1) and rate capability (1429 F g−1 even at 45 A g−1) than NCSs@Ni(OH)2. The outstanding capacitive performance of this kind of nanocomposite is due to its large surface area, optimum porous size distribution and retained flower-like morphology, especially the high electrical conductivity originating from conductive skeleton of NCSs and Co ion doping. Furthermore, using the optimized NCSs@CoxNi1-x(OH)2 and activated carbon as a positive and negative electrode, the as-prepared energy storage device achieves higher energy (16–37 Wh kg−1) and power density (8−0.4 kW kg−1), along with satisfactory cycling stability.

中文翻译：

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用于高性能超级电容器的聚多巴胺基 N 掺杂碳球@CoxNi1-x(OH)2 核壳纳米复合材料的快速大规模合成

摘要 电极材料的性能很大程度上取决于其结构，包括表面积、孔径分布和电导率。针对先进的结构，我们通过快速简单的两步法成功设计和开发了基于聚多巴胺的 N 掺杂碳球 (NCS) 和 CoxNi1-x(OH)2 的核壳纳米复合材料。首先，常规 NCS 直接来源于聚多巴胺的碳化，它为快速电子传输提供导电核心。然后，通过化学浴沉积法，由相互连接的CoxNi1-x(OH)2超薄纳米片组成的花状壳垂直均匀地接枝在NCSs基底表面，比水热合成更快更适合大规模生产. 为了通过这种快速沉淀过程获得均质的双金属氢氧化物 CoxNi1-x(OH)2，进一步分析了 Co 掺杂量对杂化物形貌、结构和电容特性的影响。结果表明，所获得的具有少量 Co 掺杂的 NCSs@CoxNi1-x(OH)2 纳米复合材料表现出令人印象深刻的增强的比电容（1 A g-1 时为 2065 F g-1）和倍率性能（1429 F g-1，即使在45 A g-1) 比 NCSs@Ni(OH)2。这种纳米复合材料优异的电容性能是由于其大的表面积、最佳的多孔尺寸分布和保留的花状形态，特别是源自 NCS 和 Co 离子掺杂的导电骨架的高电导率。此外，使用优化的 NCSs@CoxNi1-x(OH)2 和活性炭作为正负极，