Abstract The nickel-based oxides or hydroxides are considered a promising electroactive material for supercapacitor application owing to its low cost, well-defined redox activity, and prospect of controllable nanostructures. However, control of nanomorphology and uniform deposition onto a conductive substrate for Ni-based materials remains a critical challenge. Herein, we demonstrate the controlled synthesis of hierarchical nanoflake structure of NiO thin film by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method and its consequent effect on supercapacitive performances. The as-prepared NiO thin films confirmed kinetically controlled growth model for the anisotropic nanostructure through a systematic investigation of controlling reaction temperatures and times. The as-optimized binder-free NiO thin film electrodes exhibited a reversible electrochemical feature, providing a high specific capacitance of 674 F g−1 and cycling stability of 72.5% after 2000 cycles. These performances of NiO thin films were attributed to its open mesoporous and large accessible area of hierarchical nanoflakes structure, as well as the fast ion diffusion into the active sites. This work opens new avenues for the design of high capacity metal oxide thin films with hierarchical architecture for electrochemical energy storage applications.

中文翻译：

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用于超级电容器应用的 NiO 薄膜分层纳米薄片结构的可控合成

摘要 镍基氧化物或氢氧化物由于其低成本、明确的氧化还原活性和可控纳米结构的前景，被认为是一种很有前途的超级电容器电活性材料。然而，对于镍基材料，纳米形态的控制和在导电基板上的均匀沉积仍然是一个关键的挑战。在此，我们展示了通过简单且廉价的连续离子层吸附和反应 (SILAR) 方法可控合成 NiO 薄膜的分层纳米薄片结构及其对超级电容性能的影响。通过对控制反应温度和时间的系统研究，所制备的 NiO 薄膜证实了各向异性纳米结构的动力学控制生长模型。优化后的无粘合剂 NiO 薄膜电极表现出可逆的电化学特性，在 2000 次循环后提供 674 F g-1 的高比电容和 72.5% 的循环稳定性。NiO 薄膜的这些性能归因于其开放的介孔和大的分层纳米薄片结构的可及区域，以及快速的离子扩散到活性位点。这项工作为设计用于电化学储能应用的具有分层结构的高容量金属氧化物薄膜开辟了新途径。以及快速离子扩散到活性位点。这项工作为设计用于电化学储能应用的具有分层结构的高容量金属氧化物薄膜开辟了新途径。以及快速离子扩散到活性位点。这项工作为设计用于电化学储能应用的具有分层结构的高容量金属氧化物薄膜开辟了新途径。