CoFe-LDH nanocage derived from MOF coupled with CNTs as cathode catalyst for Li-O2 batteries

Abstract

Li-O₂ batteries(LOBs)have garnered substantial interest owing to their exceptional energy density. Nevertheless, the slow kinetics of discharge and recharge significantly hinder their commercial application. Herein, a one-step hydrothermal process was employed to anchor metal-organic framework (MOF)-derived CoFe-layered double hydroxides (CoFe-LDH) hollow nanocages onto carbon nanotubes, thereby improving the electrochemical efficiency of LOBs. The synthesized nanocomposite resulted in an increased specific surface area, providing more catalytically active sites and rapid diffusion pathways for lithium ions and oxygen. Owing to a synergistic effect, the CoFe-LDH@CNTs electrode, when used as a cathode in LOBs, exhibited a high initial discharge capacity (32.8 Ah g⁻¹ at 500 mA g⁻¹) and maintained 176 stable cycles at 500 mA g⁻¹ with a limited capacity of 500 mAh g⁻¹. Furthermore, the optimized d-orbital electron structure and d-band center were confirmed by density functional theory (DFT) calculations, reducing the reaction barrier and improving reactant adsorption, thus accelerating the kinetics of the catalytic reaction. This study presents an innovative strategy for designing electrocatalysts for LOBs by integrating bimetallic MOF-derived materials with carbon-based substrates.