Co‐MOF derived MoSe 2 @ CoSe 2 /N‐doped carbon nanorods as high‐performance anode materials for potassium ion batteries

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.