Hydrothermal synthesis of CuS nanochips and their nanohybrids with CNTs for electrochemical energy storage applications

The nanostructured carbonaceous materials (CNTs, graphene, and activated carbon) possess excellent conductivity, larger surface area, good chemical stability, and unique structure. Therefore, these materials have great potential to boost the electrochemical performance of the transition metals based pseudocapacitive materials. In this study, the hydrothermal method was used to prepare copper sulfide nanochips. The electrical conductivity and capacitive properties of the fabricated sample were improved by forming their nanohybrid with conductive as well as capacitive CNTs. The morphological, structural, compositional, and electrical behavior of materials was investigated by conducting various analyses. The calculated electrical conductivity value of the nanohybrid sample (2.34 ? 102 Sm? 1) was considerably higher than the bare sample (1.85 ? 10-4 Sm? 1), which ensured the existence of a positive association between cobalt sulfide nanochips and one-dimensional CNTs. During electrochemical testing, the nanohybrid sample showed a much better capacitive ability than the pristine cobalt sulfide sample due to its tuned electrical properties, hybrid composition, and constructive interaction between its supplements. More precisely, the nanohybrid sample displayed a good gravimetric capacitance (Cg) (677 Fg-1) at 1 Ag-1 and excellent capacitance retention (81.9%) at 5 Ag-1. Moreover, the nanohybrid sample showed superior cyclic-aptitude as it lost only 17.7% capacity, whereas the pristine metal sulfide sample lost nearly 36% of its initial capacity after 1000 cyclic discharge experiments. The electrochemical results showed that our synthesized sample offer excellent potential for practical application in next-generation electrochemical equipments.

Automated summary

Nanostructured carbonaceous materials, such as CNTs, graphene, and activated carbon, exhibit excellent conductivity and larger surface area, which can significantly enhance the electrochemical performance of transition metals based pseudocapacitive materials. The study successfully prepared copper sulfide nanochips via the hydrothermal method and improved their electrical conductivity and capacitive properties by forming nanohybrids with conductive CNTs. The nanohybrid sample demonstrated enhanced capacitive ability, gravimetric capacitance, and cyclic-aptitude compared to the pristine cobalt sulfide sample, showing great potential for practical application in next-generation electrochemical devices.