Abstract Although supercapacitors have been extensively investigated due to the good electrochemical performance, the awful energy density, poor cycle stability and low rate performance still remain challenges in applications. In this article, we successfully design and synthesize the hierarchical NiCo2O4@NiCo2S4 core/shell nanowire arrays on Ni foam by a special interface ion-exchange process. As supercapacitor material, it exhibits a high specific capacitance of 3176 F g−1 at a current density of 2 A g−1 and can retain 86.52% at a high current density of 10 A g−1, indicating excellent rate capability. In addition, an asymmetric supercapacitor is assembled with NiCo2O4@NiCo2S4 as the cathode electrode and porous carbon as the anode electrode and KOH solution as the electrolyte, showing a super energy density of 196.8 Wh kg−1 at 752.33 W kg−1 and a high power density of 5625.12 W kg−1 at 162.45 Wh kg−1. After 15000 cyclic voltammetry cycles at a scan rate of 60 mV s−1, 137% of initial capacitance is maintained. Theoretical analysis reveals that the diffusion-controlled reaction is dominant in the total capacitance of NiCo2O4@NiCo2S4 electrode, which may be the reason for the high specific capacitance and excellent rate capability. Thereby, these electrochemical performances demonstrate that the as-fabricated NiCo2O4@NiCo2S4 core/shell nanowire arrays are the promising candidates for high-performance supercapacitors.

中文翻译：

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通过离子交换途径制备分层 NiCo 2 O 4 @NiCo 2 S 4 核/壳纳米线阵列并应用于非对称超级电容器

摘要 尽管超级电容器因其良好的电化学性能而被广泛研究，但其能量密度差、循环稳定性差和倍率性能低等问题仍然在应用中面临挑战。在本文中，我们通过特殊的界面离子交换工艺在泡沫镍上成功设计并合成了分层 NiCo2O4@NiCo2S4 核/壳纳米线阵列。作为超级电容器材料，它在 2 A g-1 的电流密度下表现出 3176 F g-1 的高比电容，在 10 A g-1 的高电流密度下可以保持 86.52%，表明具有优异的倍率性能。此外，以NiCo2O4@NiCo2S4为阴极，以多孔碳为阳极，以KOH溶液为电解质组装的非对称超级电容器，在752时表现出196.8 Wh kg-1的超能量密度。33 W kg-1 和 162.45 Wh kg-1 时的 5625.12 W kg-1 高功率密度。在以 60 mV s-1 的扫描速率进行 15000 次循环伏安循环后，137% 的初始电容得以保持。理论分析表明，扩散控制反应在 NiCo2O4@NiCo2S4 电极的总电容中占主导地位，这可能是高比电容和优异倍率性能的原因。因此，这些电化学性能表明制造的 NiCo2O4@NiCo2S4 核/壳纳米线阵列是高性能超级电容器的有希望的候选者。理论分析表明，扩散控制反应在 NiCo2O4@NiCo2S4 电极的总电容中占主导地位，这可能是高比电容和优异倍率性能的原因。因此，这些电化学性能表明制造的 NiCo2O4@NiCo2S4 核/壳纳米线阵列是高性能超级电容器的有希望的候选者。理论分析表明，扩散控制反应在 NiCo2O4@NiCo2S4 电极的总电容中占主导地位，这可能是高比电容和优异倍率性能的原因。因此，这些电化学性能表明制造的 NiCo2O4@NiCo2S4 核/壳纳米线阵列是高性能超级电容器的有希望的候选者。