Mesh-like vertical structures enable both high areal capacity and excellent rate capability

• Published in: Journal of energy chemistry 2021-02, Vol.53, p.226-233
• Main Authors: Chen, Ruyi, Xue, Jialu, Gong, Yujiao, Yu, Chenyang, Hui, Zengyu, Xu, Hai, Sun, Yue, Zhao, Xi, An, Jianing, Zhou, Jinyuan, Chen, Qiang, Sun, Gengzhi, Huang, Wei
• Format: Article
• Language: English
• Subjects: Excellent rate capability; Hybrid supercapacitors; Mesh-like structure; Ultrahigh areal capacity; Wearable energy storage
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2020.05.035

2D mesh-like vertical structures (NiCo2S4@Ni(OH)2) with the merits of both 1D and 2D structures are designed for fabricating flexible hybrid supercapacitors, achieving rapid electrochemical kinetics without compromising mass loading. [Display omitted] •Mesh-like vertical structures composed of seamlessly interconnected NiCo2S4@Ni(OH)2 nanowires are designed.•The loadings of NiCo2S4 core and Ni(OH)2 sheath reach high levels of 1.09 mg cm−2 and 1.08 mg cm−2, respectively.•NiCo2S4@Ni(OH)2 meshes exhibit a high areal capacity and excellent rate capability. In order to balance electrochemical kinetics with loading level for achieving efficient energy storage with high areal capacity and good rate capability simultaneously for wearable electronics, herein, 2D mesh-like vertical structures (NiCo2S4@Ni(OH)2) with a high mass loading of 2.17 mg cm−2 and combined merits of both 1D nanowires and 2D nanosheets are designed for fabricating flexible hybrid supercapacitors. Particularly, the seamlessly interconnected NiCo2S4 core not only provides high capacity of 287.5 μAh cm−2 but also functions as conductive skeleton for fast electron transport; Ni(OH)2 sheath occupying the voids in NiCo2S4 meshes contributes extra capacity of 248.4 μAh cm−2; the holey features guarantee rapid ion diffusion along and across NiCo2S4@Ni(OH)2 meshes. The resultant flexible electrode exhibits a high areal capacity of 535.9 μAh cm−2 (246.9 mAh g−1) at 3 mA cm−2 and outstanding rate performance with 84.7% retention at 30 mA cm−2, suggesting efficient utilization of both NiCo2S4 and Ni(OH)2 with specific capacities approaching to their theoretical values. The flexible solid-state hybrid device based on NiCo2S4@Ni(OH)2 cathode and Fe2O3 anode delivers a high energy density of 315 μWh cm−2 at the power density of 2.14 mW cm−2 with excellent electrochemical cycling stability.