Construction of NiCoSe2 nanosheets supported on CuNi2S4 nanospheres for advanced hybrid supercapacitors

The interface engineering strategy of hybridizing transition metal sulfides (TMSs) with other electroactive materials has proven to be a powerful strategy to exploit advanced electrode materials for supercapacitors (SCs). Herein, CuNi 2 S 4 nanospheres were grown directly onto carbon cloth (CC) by a single-step electrodeposition procedure, and the bimetallic selenide NiCoSe 2 then was deposited over the CuNi 2 S 4 nanospheres to create a flexible CuNi 2 S 4 @NiCoSe 2 hybrid electrode material with special core–shell architecture. The nanoflower-like hybrid structure not only increases the redox active sites but also provides short paths for electron/ion transport and improves redox reaction kinetics. The CuNi 2 S 4 @NiCoSe 2 electrode achieves a capacity value of 979.2 C g −1 /3.43 C cm −2 at 1 A g −1 along with good rate performance, outperforming pristine CuNi 2 S 4 and NiCoSe 2 . This wonderful supercapacitive behavior is related to the synergy of CuNi 2 S 4 ’s high conductivity and NiCoSe 2 ’s high electroactivity. Furthermore, the hybrid supercapacitor using the CuNi 2 S 4 @NiCoSe 2 cathode along with the porous carbon from pine pollen anode achieves an energy density (78.9 Wh kg −1 at 720.2 W kg −1 ) and maintains 91.4 % of original capacity after 50,000 cycles. These findings affirm that the CuNi 2 S 4 @NiCoSe 2 heterostructure is structurally superior as an electrode material in advanced energy storage systems.