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

Abstract

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.

Keywords

• Ultrasonication
• Layered double hydroxides
• Nanosheets
• Supercapacitor