Superior Performance of 2D Layered Bimetallic Bismuth and Copper Oxytellurides for Supercapacitor Applications

Abstract

Widespread applications of 2D metal oxychalcogenide materials in the fields of semiconductors, thermoelectrics, and optoelectronics have raised the interest of the research community to explore more about these materials. The addition of metals and the preparation of different combinations of composite materials can effectively raise their utility. Here, the synthesis of bismuth (Bi)-and copper (Cu)-based layered oxytelluride materials is performed using the "microwave method" at a fixed power of 540 W and an irradiation time of 20 min. Good crystalline phases of the synthesized materials are obtained from the crystallographic studies, which agree well with the reported studies done previously. Morphological studies show the appearance of nanosheet-like structures in different synthesized samples. The Raman spectra of the samples demonstrate several vibrational modes. Chemical analysis confirms the valence states of the individual elements. The synthesized bismuth oxytelluride (BOT), copper oxytelluride (COT), and bismuth copper oxytelluride (BCOT) samples are investigated for supercapacitor applications. The electrochemical capacitive performance of BOT, COT, and BCOT is studied in the potential range of 0−0.6 V in an aqueous 2 M KOH electrolyte. While BOT and COT exhibit only 95 F g −1 (57 C g −1 ) and 158 F g −1 (94.8 C g −1 ), respectively, BCOT can provide a higher specific capacitance of 323 F g −1 (193.8 C g −1 ) at a specific current of 2 A g −1 , with excellent cycling stability of 90.5% after continuous 5000 cycles. Thus, this study emphasizes the better capacitive performance of bimetallic oxychalcogenides over monometallic oxychalcogenides.