High power aqueous hybrid asymmetric supercapacitor based on zero-dimensional ZnS nanoparticles with two-dimensional nanoflakes CuSe2 nanostructures

Energy storage materials, particularly chalcogenides, are fascinating electrode materials for supercapacitors (SCs) because of their high capacitance, remarkable electrical conductivity, and multiple oxidation states contributed by numerous metal cations. Herein, a novel nanocomposite based on zinc sulfide and copper dis-elenide, denoted as (ZnS-CuSe2), was prepared via a sonochemical-assisted method. The structural analysis revealed the cubic structure for pure ZnS, orthorhombic for CuSe2, and co-existing cubic and orthorhombic phases for ZnS-CuSe2 nanocomposites with high purity and crystallinity. The ZnS-CuSe2 nanocomposite offered exceptional electrochemical performance with redox peaks from the CV analysis, and coupled with plateaus in the charge/discharge profile, confirming the faradaic energy storage properties with functional reversibility. Similarly, a high conductive feature of the ZnS-CuSe2 composite was revealed by impedance study, with a minor charge transfer resistance than their bulk materials. A hybrid asymmetric supercapacitor (HASCs) composed of ZnS-CuSe2//AC was constructed, which manifested an enlarged voltage window up to 1.7 V with capacitance of 95 F g-1 and a maximum specific energy of 38 Wh kg -1. Also, high power delivery was attained at 3927 Wkg-1 when specific energy goes down to 12 Wh kg- at 5 A g-1. Interestingly, only 81.8% retention was left beneath when cycled to 8000 cycles, specifying decent stability of the ZnS-CuSe2//AC HASCs.

Automated summary

A novel nanocomposite based on zinc sulfide and copper dis-elenide (ZnS-CuSe2) was prepared and exhibited exceptional electrochemical performance and functional reversibility, making it a promising electrode material for supercapacitors.