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

Abstract

Potassium ion batteries (KIBs) have attracted considerable attention as a nextgeneration 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 MoSe 2 core and a CoSe 2 /N-doped carbon shell (denoted as MC-Se@NC) are successfully synthesized by thermal treatment of Co-based metal-organic framework (ZIF-67)-coated MoO 3 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 À1 at 0.5 A g À1 after 150 cycles, and remarkable rate capability of 190 mA h g À1 at 2.0 A g À1 . 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 largescale energy storage systems.