A core–shell structure of cobalt sulfide//G-ink towards high energy density in asymmetric hybrid supercapacitors,Sustainable Energy & Fuels

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A core–shell structure of cobalt sulfide//G-ink towards high energy density in asymmetric hybrid supercapacitors
Sustainable Energy & Fuels ( IF 5.0 ) Pub Date : 2020-07-31 , DOI: 10.1039/d0se00189a
Venkata Thulasivarma Chebrolu _{1,

2,

3,

4} , Balamuralitharan Balakrishnan _{5,

6,

7,

8} , Aravindha Raja Selvaraj _{1,

2,

3,

4} , Hee-Je Kim _{1,

2,

3,

4}

Affiliation

New atom substitution in transition metals is a promising strategy for improving the performance of supercapacitors (SCs). Herein, we developed a cobalt sulfide core–shell nanostructure composed of nanoflakes and nanoparticles on a nickel foam substrate via a simple synthetic route involving CBD and subsequent sulfide ion-exchange reaction process. The resultant cobalt sulfide nanostructure exhibited enhanced charge transfer and provided abundant active sites with the electrolyte. Consequently, the unique core–shell cobalt sulfide nanostructure demonstrated a higher specific capacity of 450 mA h g⁻¹ in comparison with that of cobalt oxide of 125 mA h g⁻¹ and cobalt selenide of 337 mA h g⁻¹ at a high current density of 5 mA cm⁻². Moreover, the cobalt sulfide electrode delivered a good rate capability of 70% of its initial capacity. The core–shell structure of cobalt sulfide was further used to assemble an asymmetric hybrid supercapacitor (AHSC) with graphene ink as the outer electrode, showing a stable and high energy density of 35.43 W h kg⁻¹ at a power density of 612.38 W kg⁻¹, which is comparatively higher than that in recent works. The device exhibited superior cyclic stability of 96% over 5000 cycles. Our results suggest that the hollow core–shell structure is a simple strategy to fabricate high-performance advanced electrode materials for energy conversion and storage technologies.

中文翻译：

硫化钴// G墨水的核-壳结构朝着不对称混合超级电容器中的高能量密度方向发展

过渡金属中的新原子取代是改善超级电容器（SC）性能的有前途的策略。在本文中，我们通过涉及CBD和随后的硫化物离子交换反应过程的简单合成路线，开发了一种由纳米薄片和纳米颗粒组成的硫化钴核-壳纳米结构，该结构位于镍泡沫基底上。所得的硫化钴纳米结构表现出增强的电荷转移，并为电解质提供了丰富的活性位。因此，在高电流密度为5的情况下，独特的核-壳型硫化钴纳米结构与125 mA hg ^-1的氧化钴和337 mA hg ^-1的硒化钴相比具有450 mA hg ^-1的更高比容量。毫安厘米⁻²。此外，硫化钴电极提供了其初始容量的70％的良好倍率能力。硫化钴的核-壳结构进一步用于组装不对称混合超级电容器（AHSC），石墨烯墨水作为外部电极，在功率密度为612.38 W kg时显示出35.43 W h kg^-1的稳定且高能量密度^-1，比最近的作品相对较高。该器件在5000次循环中表现出96％的出色循环稳定性。我们的研究结果表明，空心核壳结构是制造用于能量转换和存储技术的高性能先进电极材料的简单策略。

更新日期：2020-08-25

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