Fluorine Doped MOFs Based on Nickel and Manganese As Anode for Applications in Lithium-Ion Batteries

Abstract

Lithium-ion batteries are energy storage devices that have become a fundamental part of our daily lives due to their use in electronic devices. Many materials are currently being researched due to the new requirements that are needed for this application. Metal organic networks (MOFs) are a type of material with unique properties such as high surface area, high porosity, good crystallinity, and functionality, which are formed by joining inorganic and organic units by coordination bonds, where the inorganic units are usually metal oxides that are active sites for redox processes. Transition metals (Fe, Co, Ni, Cr, etc.) are known to be precursors in the synthesis of MOFs with electrochemical activity, the presence of these unsaturated metals in the structure of MOFs as Lewis acids improves the electrochemical activity in catalytic processes. According to the characteristics and properties of MOFs, an efficient way to increase the specific charging capacity of batteries is the introduction of other redox active sites from another metal, as well as the choice of the appropriate ligand. This research proposes the solvothermal synthesis of MOFs based on nickel and manganese, with terephthalic acid in DMF solvent, as new anodic materials. The DRX analysis show the presence of the monometallic MOFs phases in the bimetallic MOF and the FT-IR spectra show the coordination of Ni and Mn with the BDC ligand. In addition, significant increase in the electrochemical properties was developed with the addition of F-, which will cause the destruction of the coordination bond of the metals with their ligands, improving the lithiation/de-lithiation process. Due to the presence of active redox sites, the affinity of fluorine for lithium and the synergistic effect that metals present in bimetallic MOF, it is expected that this material will present improved electrochemical properties to be used as an anode in lithium-ion batteries; and by reducing the amount in the manganese ratio, the material will improve its conductivity properties.This research is supported by the world bank and Prociencia through agreement No. 045-2019 FONDECYT-BM.