Luring Magnesium into a 2D-Framework: What Makes the Bait Juicier?
Daniel Dinev, Hristo Rasheev, Radostina Stoyanova and Alia Tadjer
Abstarct: Organic compounds are in the spotlight of numerous scientific teams searching new cathode materials for metal-ion batteries. Key assets are their low-cost, environmental friendliness and easy chemical modification by functionalization with groups enhancing their redox activity. Lithium is quite expensive to purify and scarce on our planet, so alternative charge carriers are wanted for the green future of metal-ion batteries. Magnesium is nontoxic, more cost-efficient and environmentally-friendly, its ion bears twice the charge of Li and Na ions, which makes the Mg-ion storage devices a promising alternative of the traditional Liion ones. Major drawbacks of the Mg-ion batteries are electrolyte decomposition on metallic magnesium upon recharging and insufficiently studied electrode materials suitable for magnesium intercalation and deintercalation. The latter issue can be resolved by using redoxactive organic materials. Sadly, these are non-conducting and usually quite soluble in the electrolyte. To reduce solubility, we have, on the one hand, incorporated the organic molecules (quinones) in complexes with a transition metal ion (Ni(II)), and on the other hand,
we have attached the entire complex to a graphene sheet, thus endowing conductivity to the material as well. Using periodic DFT calculations (PBE), we have quantified the effect of the quinone topology and the degree of its functionalization with electron-accepting groups (-CN) on the electrochemical potential of the material and its theoretical capacity for magnesium uptake.
Acknowledgements: The authors acknowledge the funding provided by the Bulgarian National Science Fund, project CARiM-VIHREN, grant number КП06-ДВ-6/16.12.2019.
The authors from CARiM’s Research Team are bolded.
VIHREN-CARiM 2019 