Hybrid Cobalt(II) Fluoride Derived from a Bimetallic Zeolitic Imidazolate Framework as a High-Performance Cathode for Lithium–Ion Batteries

Abstract

In this work, a new design of a zeolitic imidazolate framework-derived CoF2/Fe2O3 hybrid structure is reported via a simple copyrolysis strategy. The in situ generated C/N doped framework effectively enhances its own conductivity and offers more Li+-active insertion sites. The distinctive nanoscale structure not only provides adequate space to accommodate volume changes, but also promotes electrolyte penetration into the electrode, leading to higher utilization of active materials and faster ion/electron transfer during cycling. As a result, an improved electrochemical performance of 130.4 mA h g–1 was obtained after 400 relatively long-term cycles at a current density of 100 mA g–1. Additionally, the surface-induced capacitive feature and profitable lithium ion diffusion (DLi+) coefficient give further insights into the lithium storage mechanism of the fabricated electrode. We believe that this novel strategy may shed light into fabricating promising electrode materials derived from metal–organic frameworks for energy storage.