Computational modelling of metal complexes with redox-active ligands for Li-ion batteries
Y. Danchovski*, H. Rasheev*, R. Stoyanova* and A. Tadjer*
Inorganic materials used for fabrication of electrodes in Li-ion energy storage devices are known for decades. The utilization of organic compounds for the same purpose is an innovative approach which is deemed to result in the production of batteries with superior quality. Organic materials are both easily modelled and manufactured, their structure is synthetically tuneable, they are light-weight and recyclable. Combining a transition metal with redox-active organic ligands leads to a complex compound with multiple redox stages, involving both the ligands and the metal ion. Indeed, these compounds, offer a unique opportunity to design a new material with higher electrochemical activity and better characteristics.
The current study addresses complexes of nickel and vanadium with a benzoquinone-derived ligand and evaluates their electrochemical potential in the reduction with Li. Complexes of two ligands with each metal ion in two oxidation states are constructed. DFT calculations are performed to optimize the structure of the complexes at several consecutive degrees of reduction with Li and the electrochemical potential of each stage was quantified. Besides energetics, the changes in spatial structure and electron density distribution were monitored. The modelled complexes of both metals exhibited potential for substantial Li intercalation retaining structural stability. The computed electrode potentials and capacities bear promise for possible exploitation of these complexes as efficient electrode materials. The combination of two types of redox-active components proves to be a successful strategy for design of prospective materials for enhanced energy storage and conversion.
The authors from CARiM’s Research Team are noted with *