Molecular dynamics of hybrid ionic materials for lithium battery

Abstract

Ionic liquids have the ability to dissolve ions, such as, lithium salts. This makes them suitable electrolytes for lithium battery. These electrolytes have a characteristic feature to form ionic clusters due to the strong interaction between lithium and anions. Regarding their use as electrolyte for lithium battery, the lithium clustering effect leads to a decrease in ionic conductivity. In this context, new materials which are able to interact less effectively with lithium ion are highly requested. In this project we propose computational study of new materials with potential ability to decrease the lithium - anion interaction, decreasing the ion clustering. The materials we are concerned about in this project are ionic liquids bearing (-CH2CH2O-)n side chains, where n =2,4 or 6. Oxygen atoms in the side chain of cations would allow a less energetic favourable interaction between lithium ion and anions, decreasing the ion clustering previously mentioned. Nanocomposite formed by clays and poly(ethyleneoxide), PEO, has higher ionic conductivity than the polymer electrolyte PEO/LiBF4 at room temperature. Hybrid materials can be obtained by mixing ionic liquids and clays, which will be exploited as potential electrolyte for lithium battery. A different aspect to be studied concerns polarizable models for ionic liquids from ab initio calculations, using an approach that has been developed in colaboration with Prof. Paul Maddens group at University of Edinburgh. (AU)