A research team led by Prof. WANG Hui, in collaboration with Prof. ZHENG Fangcai from the High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, has developed a new way to improve sodium–sulfur battery performance by changing the atomic structure of a catalyst.
The study was published in Angewandte Chemie.
Main-group metal single-atom catalysts are attractive for sodium–sulfur batteries because they are relatively inexpensive and have low toxicity. However, their catalytic activity remains limited, and the interactions between p-block metal atoms and sodium polysulfides formed during battery operation are not yet fully understood.
In this study, the researchers modified the atomic structure around individual aluminum (Al) atoms. They introduced nitrogen atoms into an existing structure in which each Al atom was surrounded by four oxygen atoms, replacing one oxygen atom with nitrogen. This created an asymmetric structure with three oxygen atoms and one nitrogen atom around each Al atom.
The change altered the distribution of electrons around the Al atoms, strengthening their interaction with sodium polysulfides. As a result, fewer polysulfides escaped from the cathode, while the reactions involved in battery operation proceeded more efficiently.
The batteries also maintained stable performance over thousands of charge-discharge cycles, showing good potential for long-lasting sodium–sulfur batteries.
The findings highlight the importance of the local atomic environment in determining the catalytic activity of single-atom catalysts and offer new possibilities for designing efficient catalysts based on main-group metals.
This illustrates the synthesis schematic, structural characterization, electron transfer process during Na2S6 adsorption, and the p–p orbital hybridization interaction between Al single atoms and sodium polysulfides. (Image by ZHENG Fangcai)
