Bond modulation of MoSe driving combined intercalation and conversion reactions for high-performance K cathodes.

The urgent demand for large-scale global energy storage systems and portable electronic devices is driving the need for considerable energy density and stable batteries. Here, Se atoms are introduced between MoSe layers (denoted as MoSe ) by bond modulation to produce a high-performance cathode for potassium-ion batteries. The introduced Se atoms form covalent Se-Se bonds with the Se in MoSe, and the advantages of bond modulation are as follows: (i) the interlayer spacing is enlarged which increases the storage space of K; (ii) the system possesses a dual reaction mechanism, and the introduced Se can provide an additional conversion reaction when discharged to 0.