Tuning Hierarchical Ferric Nanostructures-Decorated Diatomite for Supercapacitors

FeOOH nanosheets on porous diatomite have been successfully prepared by a facile two-step hydrothermal approach for supercapacitors, and then α-Fe₂O₃ and γ-Fe₂O₃ nanostructures are obtained via calcination under different atmospheres and temperatures. The morphologies and structures of all the samples are investigated in detail to make the hierarchical architecture clear. Besides, systemic tests are carried out in 1 M Na₂SO₄ electrolyte to characterize the electrochemical properties of these materials. Among the iron-related composite electrodes, diatomite@FeOOH owns the highest specific capacitance (157.9 F g^-1 at a current density of 0.5 A g^-1) and best cycling performance (98.95% retention after 1000 cycles), which is considered to be a potential material for high-performance supercapacitors. Furthermore, the synthesizing strategy can be extended to the preparation of other metallic oxide-derived functional materials towards energy storage and conversion.