Green Fabrication of Nickel-Iron Layered Double Hydroxides Nanosheets Efficient for the Enhanced Capacitive Performance

Rational synthesis of robust layered double hydroxides (LDHs) nanosheets forhigh-energy supercapacitors is full of challenges. Herein, we reported anultrasonication-assisted strategy to eco-friendly fabricate NiFe-LDHsnanosheets for the enhanced capacitive behavior. The experimental resultscombined with different advanced characterization tools document that theutilization of ultrasonication has a profound effect on the morphology andthickness of the as-obtained NiFe-LDHs, alternatively affecting the capacitivebehavior. It shows that NiFe-LDHs nanosheets prepared with 2-h ultrasonictreatments display the exceptional capacitive performance because of thesynergetic effect of ultrathin thickness, large specific surface area, and highmesoporous volume. The maximum specific capacitance of Ni3Fe1-LDHs nanosheetswith the thickness of 7.39 nm and the specific surface area of 77.16 m2 g-1reached 1923 F g-1, which is competitive with most previously reported values.In addition, the maximum specific energy of the assembled NiFe-LDHs//ACasymmetric supercapacitor achieved 49.13 Wh kg-1 at 400 W kg-1. This workprovides a green technology to fabricate LDHs nanosheets, and offers deepinsights for understanding the relationship between the morphology/structureand capacitive behavior of LDHs nanosheets, which is helpful for achievinghigh-performance LDHs-based electrode materials.