Green fabrication of nickel-iron layered double hydroxides nanosheets efficient for the enhanced capacitive performance

• Published in: Green energy & environment 2022-10, Vol.7 (5), p.1053-1061
• Main Authors: Wang, Yuchen, Chen, Zuo, Zhang, Man, Liu, Yaoyu, Luo, Huixia, Yan, Kai
• Format: Article
• Language: English
• Subjects: Layered double hydroxides; Nanosheets; Supercapacitor; Ultrasonication
• ISSN: 2468-0257; 2468-0257
• DOI: 10.1016/j.gee.2021.01.019

Rational synthesis of robust layered double hydroxides (LDHs) nanosheets for high-energy supercapacitors is full of challenges. Herein, we reported an ultrasonication-assisted strategy to eco-friendly fabricate NiFe-LDHs nanosheets for the enhanced capacitive behavior. The experimental results combined with different advanced characterization tools document that the utilization of ultrasonication has a profound effect on the morphology and thickness of the as-obtained NiFe-LDHs, alternatively affecting the capacitive behavior. It shows that NiFe-LDHs nanosheets prepared with 2-h ultrasonic treatments display the exceptional capacitive performance because of the synergetic effect of ultrathin thickness, large specific surface area, and high mesoporous volume. The maximum specific capacitance of Ni3Fe1-LDHs nanosheets with the thickness of 7.39 nm and the specific surface area of 77.16 m2 g−1 reached 1923 F g−1, which is competitive with most previously reported values. In addition, the maximum specific energy of the assembled NiFe-LDHs//AC asymmetric supercapacitor achieved 49.13 Wh kg−1 at 400 W kg−1. This work provides a green technology to fabricate LDHs nanosheets, and offers deep insights for understanding the relationship between the morphology/structure and capacitive behavior of LDHs nanosheets, which is helpful for achieving high-performance LDHs-based electrode materials. The nickel-iron layered double hydroxides (NiFe-LDHs) nanosheets were synthesized with a facile and eco-friendly ultrasonication-assisted methodology. The asymmetric supercapacitor assembled by NiFe-LDHs nanosheets and commercial activated carbon delivered a maximum specific energy of 49.13 Wh kg−1. [Display omitted]