Construction of sulfur vacancies enriched hollow zinc cobalt bimetallic sulfides for high-performance supercapacitors

• Published in: Journal of alloys and compounds 2022-08, Vol.913, p.165191, Article 165191
• Main Authors: Qian, Xingyue, Yin, Yixuan, Lu, Yuchen, Xia, Jiawei, Huang, Bingji, Sun, Jingwen, He, Guangyu, Chen, Haiqun
• Format: Article
• Language: English
• Subjects: Bimetals; Capacitance; Charge transport; Cobalt sulfide; Electrochemical analysis; Energy storage; Hollow nanostructure; Hybrid supercapacitors; Metal-organic frameworks; Sulfides; Sulfur; Sulfur vacancy; Supercapacitors; Vacancies; Vulcanization; Zinc; Zinc cobalt sulfides
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.165191

Designing bimetallic sulfide materials with well-defined nanostructure and high energy density is indeed desirable for high-performance supercapacitors. Here, a hollow zinc cobalt sulfide (ZnxCo3−xS4) dodecahedron with plentiful sulfur vacancies is synthesized through a co-precipitation approach followed by a solvothermal vulcanization treatment. The tailored hollow structure can effectively accelerate the charge transport and facilitate the diffusion of OH-, whereas the sulfur vacancies significantly increase the amount of contact active sites and enhance the electronic conductivity. Both of the features can simultaneously promote the capacitance performance of ZnxCo3−xS4 for supercapacitors, where the most-performing Zn0.3Co2.7S4 electrode, achieves a high specific capacitance of 545.9 C g−1 in 3 M KOH electrolyte at the current density of 1 A g−1 and excellent long-term durability of 84.7% capacity retention after 1000 cycles. Particularly, the assembled aqueous hybrid supercapacitors delivers high energy density and superior cyclic stability. This study demonstrates a rational design of well-controlled bimetallic sulfides with outstanding electrochemical performance for energy storage devices. [Display omitted] •The hollow ZnxCo3−xS4 was synthesized through a co-precipitation followed by a solvothermal vulcanization treatment.•The S-vacancies and hollow structure simultaneously enhanced the capacitance performance of ZnxCo3−xS4.•The assembled hybrid supercapacitor delivered a competitive energy density.