Hierarchical Nickel-Cobalt Hydroxide Composite Nanosheets-Incorporated Nitrogen-Doped Carbon Nanotubes Embedded with Nickel-Cobalt Alloy Nanoparticles for Driving a 2 V Asymmetric Supercapacitor.
Hierarchical Nickel-Cobalt Hydroxide Composite Nanosheets-Incorporated Nitrogen-Doped Carbon Nanotubes Embedded with Nickel-Cobalt Alloy Nanoparticles for Driving a 2 V Asymmetric Supercapacitor.
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DOI：
10.1021/acsami.2c18237
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发表时间：
2023-01
影响因子：
9.5
通讯作者：
Zijun Shi;Xuang-Long Xu;P. Jing;Baocang Liu;Jun Zhang
中科院分区：
文献类型：
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作者：
Zijun Shi;Xuang-Long Xu;P. Jing;Baocang Liu;Jun Zhang
为了显著提高超级电容器的容量，需要一种结构和成分良好、具有很强的电化学性能的电极材料。在本研究中，建立了一种创造性的技术，以碳布为衬底，制备出具有多孔结构和良好导电性的镍钴合金纳米颗粒包裹的N掺杂碳纳米管(NiCo@NCNTs/CC)。然后，采用简单的电沉积方法在NiCo@NCNTs/CC上制备了镍钴层状双氢氧化物(NiCo-LDH)纳米片，构建了NiCo-LDH/NiCo@NCNTs/CC自支撑整体式层状纳米片/纳米管复合电极。在这种复合电极中，NiCo@NCNTs可以作为良好的导体和结构支架，生长出具有三维开孔结构的NiCo-LDH纳米片，这有助于提高NiCo-LDH纳米片的电子/离子转移性能，增加暴露的反应部位的数量，抑制NiCo-LDH纳米片的聚集，从而提高电容和稳定性。作为正极，NiCo-LDH/NiCo@NCNTs/CC分级纳米片/纳米管电极具有1898mF cm-2(1262Ag-1)的高容量，长期稳定性好，8000次循环后的容量保持率约为100%，库仑效率接近103%。用Co(OH)2/NiCo@NCNTs/CC负极组装成非对称超级电容器后，获得了2V的工作电压和73.1Wh cm-2(52.8Wh kg-1)的能量密度。我们的研究为构建高性能超级电容器的过渡金属化合物-碳材料集成复合电极提供了一条潜在的途径。
A class of electrode materials with favorable structures and compositions and powerful electrochemical (EC) properties are needed to boost the supercapacitor capacity significantly. In this study, an inventive technique was established to produce a well-aligned nickel-cobalt alloy nanoparticles-encapsulated N-doped carbon nanotubes with porous structure and good conductivity on carbon cloth (NiCo@NCNTs/CC) as a substrate. Then, nanosheets of nickel-cobalt layered double hydroxide (NiCo-LDH) were grown on NiCo@NCNTs/CC via a simple EC deposition method to construct a self-supported monolithic hierarchical nanosheets/nanotubes composite electrode of NiCo-LDH/NiCo@NCNTs/CC. In such a composite electrode, the NiCo@NCNTs can act as a good conductor and structural scaffold to grow NiCo-LDH nanosheets with a three-dimensional open and porous structure, which helps to improve the electron/ion-transfer performance, increase the number of exposed reactive sites, and inhibit the aggregation of NiCo-LDH nanosheets, thereby boosting the capacitance and stability. As a positive electrode, the NiCo-LDH/NiCo@NCNTs/CC hierarchical nanosheets/nanotubes electrode displays 1898 mF cm-2 (1262 A g-1) of high capacitance, long-term stability with a capacitance retention of around 100% after 8000 cycles, and nearly 103% Coulombic efficiency. After assembling into an asymmetric supercapacitor with a Co(OH)2/NiCo@NCNTs/CC negative electrode, 2 V of operating voltage with 73.1 μW h cm-2 (52.8 W h kg-1) of energy density was achieved. Our investigation gives a potential approach for constructing the integrated composite electrode of transition-metal compounds-carbon materials for high-performance supercapacitors.