Co‐MOF derived MoSe2@CoSe2/N‐doped carbon nanorods as high‐performance anode materials for potassium ion batteries.

Summary: Potassium ion batteries (KIBs) have attracted considerable attention as a next‐generation large‐scale energy storage system. Due to the large diameter of K+ ions, developing advanced electrode materials to achieve high‐performance KIBs is challenging. In this paper, one‐dimensional (1D) hybrid nanostructures comprising a MoSe2 core and a CoSe2/N‐doped carbon shell (denoted as MC‐Se@NC) are successfully synthesized by thermal treatment of Co‐based metal‐organic framework (ZIF‐67)‐coated MoO3 nanorods. The unique 1D morphology and synergistic effect between the different elements provide sufficient electrochemical reaction sites and facilitate the reaction kinetics. Further, the N‐doped carbon coating alleviates the volume fluctuation and pulverization of the active materials during cycling and improves the electrode conductivity. Accordingly, when applied to KIBs, the MC‐Se@NC anode delivers a high reversible capacity of 327 mA h g−1 at 0.5 A g−1 after 150 cycles, and remarkable rate capability of 190 mA h g−1 at 2.0 A g−1. Furthermore, to explore the practical application of MC‐Se@NC anode, a K‐ion full cell consisting of MC‐Se@NC anode and Prussian blue cathode is fabricated and characterized. As a demonstration, a light‐emitting diode (LED) is successfully powered by the K‐ion full cell. These excellent electrochemical properties of MC‐Se@NC present possibilities for the commercialization of KIB‐based large‐scale energy storage systems. [ABSTRACT FROM AUTHOR]