CuCo₂S₄ nanotubes on carbon fiber papers for high-performance all-solid-state asymmetric supercapacitors

In this study, CuCo₂S₄ directly grown on carbon fiber papers (CFP) were prepared by a low-cost hydrothermal method. We also studied the influence of two different sulfur sources on the morphology and performance of CuCo₂S₄. Compared to TAA as sulfur source, the performance and morphology of CuCo₂S₄ by Na₂S·9H₂O are better. The CuCo₂S₄–Na₂S nanotubes possess irregular diameters from 100 to 200 nm. An electrode made of the synthesized CuCo₂S₄–Na₂S nanotubes/CFP composite exhibits a maximum specific capacitance of 456 F g⁻¹ at 1 A g⁻¹ and 83% of capacitance retention after 5000 cycles at 5 A g⁻¹. The synthesized CuCo₂S₄–Na₂S/CFP is used to construct an all-solid-state asymmetric supercapacitor (ASC) as the positive electrode, while and the negative electrode is made of a Fe₂O₃/reduced graphene oxide (rGO) composite on Ni foam. This asymmetric device has delivered an energy density of 50 W h kg⁻¹ and a power density of 700 W kg⁻¹ at an operating voltage of 1.5 V. It retains a long cycling life—78.2% capacity retention ratio after 5000 cycles. This work demonstrates the feasibility of the CuCo₂S₄–Na₂S nanotubes in the applications of high-performance supercapacitors.