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Self‐assembly of subnanometer (sub‐1 nm) scale polyhedral building blocks can yield some superstructures with novel and interesting morphology as well as potential functionalities. However, achieving the self‐assembly of sub‐1 nm polyhedral building blocks is still a great challenge. Herein, through encapsulating the titanium‐substituted polyoxometalate (POM, K7PTi2W10O40) with tetrabutylammonium cations (TBA+), we first synthesized a sub‐1 nm rhombic dodecahedral building block by further tailoring the spatial distribution of TBA+ on the POM. Molecular dynamics (MD) simulations demonstrated the eight TBA+ cations interacted with the POM cluster and formed the sub‐1 nm rhombic dodecahedron. As a result of anisotropy, the sub‐1 nm building blocks have self‐assembled into rhombic dodecahedral POM (RD‐POM) assemblies at the microscale. Benefiting from the regular structure, Br− ions, and abundant active sites, the obtained RD‐POM assemblies exhibit excellent catalytic performance in the cycloaddition of CO2 with epoxides without co‐catalysts. This work provides a promising approach to tailor the symmetry and structure of sub‐1 nm building blocks by tuning the spatial distribution of ligands, which may shed light on the fabrication of superstructures with novel properties by self‐assembly. [ABSTRACT FROM AUTHOR]

Highlights: Bi2S3 is proposed as a promising cathode material for rechargeable aqueous Zn ion battery. The Zn/Bi2S3 battery shows a reversible capacity of 161 mAh g−1 at 0.2 A g−1 and good cyclic stability of up to 100 cycles with ca. 100% retention. The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. Aqueous Zn ion batteries (ZIBs) are promising in energy storage due to the low cost, high safety, and material abundance. The development of metal oxides as the cathode for ZIBs is limited by the strong electrostatic forces between O2− and Zn2+ which leads to poor cyclic stability. Herein, Bi2S3 is proposed as a promising cathode material for rechargeable aqueous ZIBs. Improved cyclic stability and fast diffusion of Zn2+ is observed. Also, the layered structure of Bi2S3 with the weak van der Waals interaction between layers offers paths for diffusion and occupancy of Zn2+. As a result, the Zn/Bi2S3 battery delivers high capacity of 161 mAh g−1 at 0.2 A g−1 and good cycling stability up to 100 cycles with ca. 100% retention. The battery also demonstrates good cyclic performance of ca. 80.3% over 2000 cycles at 1 A g−1. The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. This work indicates that Bi2S3 shows great potential as the cathode of ZIBs with good performance and stability. [ABSTRACT FROM AUTHOR]

Highlights: Bi2S3 is proposed as a promising cathode material for rechargeable aqueous Zn ion battery. The Zn/Bi2S3 battery shows a reversible capacity of 161 mAh g−1 at 0.2 A g−1 and good cyclic stability of up to 100 cycles with ca. 100% retention. The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. Aqueous Zn ion batteries (ZIBs) are promising in energy storage due to the low cost, high safety, and material abundance. The development of metal oxides as the cathode for ZIBs is limited by the strong electrostatic forces between O2− and Zn2+ which leads to poor cyclic stability. Herein, Bi2S3 is proposed as a promising cathode material for rechargeable aqueous ZIBs. Improved cyclic stability and fast diffusion of Zn2+ is observed. Also, the layered structure of Bi2S3 with the weak van der Waals interaction between layers offers paths for diffusion and occupancy of Zn2+. As a result, the Zn/Bi2S3 battery delivers high capacity of 161 mAh g−1 at 0.2 A g−1 and good cycling stability up to 100 cycles with ca. 100% retention. The battery also demonstrates good cyclic performance of ca. 80.3% over 2000 cycles at 1 A g−1. The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. This work indicates that Bi2S3 shows great potential as the cathode of ZIBs with good performance and stability. [ABSTRACT FROM AUTHOR]