F-Doped Enhanced Dual Reduction Center Metal–Organic Framework for Aqueous Aluminum Ion Batteries

Metal–organic frameworks (MOFs) with characteristics of metal ion hosts and organic ligand guests show promising applications in aqueous aluminum ion batteries (AAIBs). However, the sluggish kinetics and poor stability have detrimental effects on their practical application. Herein, an F-doped manganese-based metal–organic framework (Mn-MOF-74) was synthesized via a hydrothermal method. Mn-MOF-74 provides additional redox sites. Due to the high electronegativity of F and the high bond energy of C–F, the F-doping strategy has successfully improved the kinetics and stability. Electrochemical analysis and density functional theory (DFT) calculations jointly demonstrate the activation process of Mn-MOF-74. In addition, the energy storage mechanism has been systematically investigated by ex situ characterization. The organic linker provides additional active sites in which C═O and C–O undergo reversible changes. This work provides not only a feasible way to improve cycling stability but also a deeper understanding of the reaction mechanism related to MOFs in AAIBs.