Synthesis and Electrochemical Performance of Manganese Oxide as Additive for Cathode Material for Lithium-Sulfur Batteries

MICAELA SOLEDAD ALVAREZ; MARIELA GISELA ORTIZ; JAVIER IGNACIO AMALVY

Mar del Plata

Congreso; 34th Topical Meeting of the International Society of Electrochemistry; 2023

International Society of Electrochemistry

Rechargeable lithium batteries, particularly Li-ion technology, have been used for some time as electrochemical devices for to store energy, in mobile and stationary applications. Although, to achieve high conversion efficiency and maximum current delivered rate in electrochemical devices, it is required to minimize the energy losses of the processes involved. Hence, the development of new materials with stable composition and surface structure are necessary to optimize energy conversion and storage capacity.Sulfur can supply a theoretical capacity of 1675 mAhg-1 and a specific energy of 2600 WhKg-1 [1], values notably higher than those supplied by lithium-ion batteries. The lithium-sulfur battery has been investigated by different groups in past decades [2]. However, many of these studies are limited to conventional configurations based on S as positive electrode, metallic Li as negative electrode and a solution of a Li salt in organic solvents as electrolyte. There are serious drawbacks, not yet overcome, that limit the practical development of the lithium-sulfur battery, such us: (i) the low electrical conductivity of the sulfur and the sulfide formed [3], (ii) significant structural and volume changes during the reaction [4], (iii) formation of lithium polysulfides during the charge-discharge process that are soluble in the organic electrolyte, thus producing a loss of active material in the cathode, (iv) soluble polysulfides can be deposited on the anode surface giving rise to corrosion problems and an increase in the internal resistance of the cell with its consequent loss in charge-discharge capacity [5].In this contribution we present the preparation and characterization of manganese oxide [6] as additive for cathodes materials in lithium-sulfur batteries. Manganese oxide was synthesized by oxidation of manganese carbonate and its subsequent selective removal with hydrochloric acid. The cathode material was synthesized by 70 wt% of powdered sulfur and 30 wt% manganese oxide mixed in a ball mill. Then, this was calcined in argon atmosphere at 155°C, for 6 hours.The electrodes were made by coating of a slurry mix on an aluminum current collector, then dried and pressed. The slurry mix was prepared with 80 wt% of the active material powder (S) and 10 wt% conductive additive powder (Super P carbon) with the binder solution of N-methylpyrrolidone and 10 wt% poly-vinylidene fluoride (PVDF). This cathode material was characterized with scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and electrochemical techniques such as, cyclic voltammetry and electrochemical impedance spectroscopy.