Design of Electrode Materials for Lithium-Ion Batteries: The Example of Metal−Organic Frameworks

Abstract

In the field of energy storage and Li-ion batteries, searching for new (positive) electrode materials with better electrochemical performances than those of transition-metal oxides is of permanent concern. To that aim, very simple concepts of chemical bonding can be used to find out the origin of the electrode limitations and to guide experimentalists for the design of new promising materials. This local approach was recently applied to hybrid architectures, such as metal−organic frameworks (MOFs), and allowed some of us to demonstrate the first reversible lithium insertion into the MIL53(Fe) positive electrode. In this paper, we combine first-principles density functional calculations and local chemical bond analyses to fully interpret the redox mechanism of this material. Its reactivity versus elemental lithium is investigated as a function of (i) the lithium composition from xLi/Fe = 0−1, (ii) the lithium distribution over the most probable Li sites, and (iii) the OH/F substitution ratio along the redo...