@article{Li2024, 
author = {Rui Li and Yulei Shi and Famin Yu and Rui Wang and Haitao Yan and Boon K. Teo and Zhigang Wang},
title = {Understanding Bonding Nature of α-Keggin Polyoxometalates [XW12O40]n− (X = Al, Si, P, S): A Generalized Superatomic Perspective},
year = {2024},
journal = {Energy & Environmental Materials},
volume = {7},
number = {6},
keywords = {first principles, molecular orbital, polyoxometalate, redox activity, superatom},
url = {https://www.sciopen.com/article/10.1002/eem2.12754},
doi = {10.1002/eem2.12754},
abstract = {α-Keggin polyoxometalates (POMs) [XW12O40]n− (X = Al, Si, P, S) are widely used in batteries owing to their remarkable redox activity. However, the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature. Here, first-principles calculations show that XW12 are core–shell structures composed of a shell and an XO4n− core, both are stabilized by covalent interactions. Interestingly, owing to the presence of a substantial number of electrons in W12O36 shell, the frontier molecular orbitals of XW12 are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model. Detailed analysis indicates that energetically high lying filled molecular orbitals (MOs) have reached unusually high-angular momentum characterized by quantum number K or higher, allowing for the accommodation of numerous electrons. This attribute confers strong electron acceptor ability and redox activity to XW12. Moreover, electrons added to XW12 still occupy the K orbitals and will not cause rearrangement of the MOs, thereby maintaining the stability of these structures. Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.}
}