Electrochemical prepared phosphorene as a cathode for supercapacitors

As a new member of 2D materials, the phosphorene possesses many unique characteristics compared with other carbon-based materials, which is strongly correlated to the structure and the electronic properties of phosphorus, can enable its use in electrochemical energy storage devices. Herein, we present a simpler approach to prepare phosphorene and then use it as an electrode in a new supercapacitor, which has a battery performance but works via the redox reaction of iodide ions on the interface of phosphorene electrode and electrolyte. The phosphorene is prepared by an electrochemical cathodic exfoliation method and the exfoliation mechanism is discussed. The high-quality phosphorene can be obtained within 5 min without ultrasonication and the yield is ∼93.1%. The dimension of phosphorene reaches micrometer grade. By virtue of the merit of the great electrocatalysis effect of phosphorene to iodide ions, the specific discharge capacity reaches to 3181.5 F/g in a three-electrode system and the largest specific energy density is 203.7 Wh/kg in an asymmetric hybrid system.