Mixed Anion Cathodes · Designing of Novel Mixed Anion Compounds as High Voltage and High Energy Density Sodium-ion Battery Cathodes

Designing of Novel Mixed Anion Compounds as High Voltage and High Energy Density Sodium-ion Battery Cathodes

(i) What is the problem/issue being addressed?: The energy density of a battery is E(q)*Q(I), where E(q) is the average voltage over the state of charge (q) of the battery, and Q(I) is the capacity at a delivered current (I) of the electric power stored per unit weight and/or volume of the battery stack of cells. Safety concerns and energy density requirements dictate the development of a dendrite-free anodes and a high-voltage cathode host into which Li+/Na+ can be inserted reversibly over a large voltage range. In this context, this project is addressed to develop high voltage cathodes and high-capacity anode to harness high energy density alkali-metal-ion batteries by partial substitution with fluorine to increase the intercalation voltage reflecting in enhanced specific energy density. Therefore, we proposed a cost effective and safe methods in preparing the electrode materials by milder processes, such as the one proposed here. (ii) Why is it important for society?: The demand to nullify the greenhouse gases emissions due to climate change without compromising on the Europe’s growing energy demand of 735 GW by 2050 have increased the dependency of renewable energy sources. However, these are intermittent/seasonal and hence, required high energy density storage devices such as batteries. Lithium-ion battery (LIBs) are considered top-notched technology to have powered portable electronics due to their high energy and power density and are therefore, being pursued to electrify plug-in electric vehicles (EVs). However, the current state-of-art LIBs consisted of rare-group elements (Li and Co) which are non-sustainable, scare, non-recyclable and hence, costs high with its growing demand to build EVs. Sodium-ion battery (SIBs) similar in-line with LIBs is considered an alternative due to vast abundance of sodium deposit and hence costs low. However, due to low electrochemical potential (-2.71 V) and large-atomic radius of Na+ couldn’t enable SIB to be used for EVs but could be used for stationary off-grid storage appliances where volume doesn’t matter. With overwhelming increase in global energy consumption, the urge to develop clean technology to store electrical energy from renewable sources are needed as they are crucial to succeed in the decarbonization of energy. Our project to develop high density lithium/sodium batteries is par in alliance with the European policy for off-grid energy storage applications. (iii) What are the overall objectives?: To develop new synthesis routes to oxyfluorides, by fluorinating layered or tunnel structure of vanadium oxide and to investigate the electrochemical performances of the new oxyfluorides (in half cell configurations) in connection with their structures, microstructure, and morphology. And finally, to investigate the electrochemical performances of full sodium cells with the new materials as positive electrode.

Data: CORDIS, © European Union