Construction of Sulfur Vacancies Enriched Hollow Zinc Cobalt Bimetallic Sulfides for High-Performance All-Solid-State Supercapacitors

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 the features simultaneously promote the capacitance performance of ZnxCo3-xS 4 for supercapacitors, where the most-performing Zn0.3 Co2.7S4 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 all-solid-state 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