Sulfur vacancies enriched Nickel-Cobalt sulfides hollow spheres with high performance for All-Solid-State hybrid supercapacitor

To pursue excellent performance of supercapacitor, an electrode material with designed morphology and tailored intrinsic properties is indeed desired. Herein, nickel-cobalt sulfides hollow spheres decorated with rich sulfur vacancies r-NiCo2S4 HSs) are prepared via an anion exchange of Ni-Co coordination polymer spheres, combined with wet chemical reduction. The r-NiCo2S4 HSs sample delivers excellent performance as an electrode: it possesses a high specific capacity (763.5C g(-1) at 1 A/g), favorable cyclability (91.40% after 5000 cycles at 10 A/g) and rate capacity (522.68C g(-1) at 15 A/g). Additionally, an all-solid-state hybrid supercapacitor device, assembled with r-NiCo2S4 HSs as the positive electrode and N/S co-doped activated carbon nanosheets as the negative electrode, presents an excellent energy density of 50.76 Wh kg(-1) under 800 W kg(-1) and feasible stability. Thus, combining hollow structure with sulfur vacancies could not only increase more active sites and ensure sufficient redox reactions, but also enhance electronic conductivity, facilitate ions / electrons transport and shorten diffusion path, which could be regarded as a promising approach to develop electrode materials with outstanding performance. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, hollow spheres of nickel-cobalt sulfides decorated with sulfur vacancies were prepared as electrode materials for supercapacitors, showing excellent performance in terms of specific capacity, cyclability, and rate capacity. Furthermore, an all-solid-state hybrid supercapacitor device assembled with these materials exhibited outstanding energy density and stability, demonstrating the potential of combining hollow structures with sulfur vacancies for developing high-performance electrode materials.