Molecular Insights into Alkali Metal Interaction with Redox Active Covalent Organic Framework as Cathode in Batteries.

Abstract

Covalent organic frameworks (COFs) based organic electrodes have emerged as promising electrode candidates for the development of next generation alkali metal ion batteries. We have employed density functional theory (DFT) based calculations to investigate the interaction of alkali metal atoms with one redox active, crystalline, experimentally synthesized COF, namely TQBQ, which consists of triquinoxalinylene and benzoquinone units in the skeleton. The electrochemical properties such as average adsorption energy, average voltage and volume change in terms of structure distortion are computed to explore its feasibility as cathode for lithium (Li), sodium (Na) and potassium (K) ion batteries. We show that among three alkali metal atoms (Li, Na and K), the TQBQ-COF would be a better candidate as cathode for potassium ion battery owing to higher average voltage and minimal volume change.