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

M. S. ALVAREZ; ORTIZ, MARIELA G.; J. AMALVY

Mar del Plata

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

INTEMA- Universidad Nacional de Mar del Plata

Rechargeablelithium batteries, particularly Li-ion technology, have been used for some timeas electrochemical devices for to store energy, in mobile and stationaryapplications. Although, to achieve high conversion efficiency and maximumcurrent delivered rate in electrochemical devices, it is required to minimizethe energy losses of the processes involved. Hence, the development of newmaterials with stable composition and surface structure are necessary tooptimize energy conversion and storage capacity.Sulfur cansupply a theoretical capacity of 1675 mAhg-1 and a specific energyof 2600 WhKg-1 [1], values notably higher than those supplied bylithium-ion batteries. The lithium-sulfur battery has been investigated bydifferent groups in past decades [2]. However, many of these studies arelimited to conventional configurations based on S as positive electrode,metallic Li as negative electrode and a solution of a Li salt in organicsolvents as electrolyte. There are serious drawbacks, not yet overcome, thatlimit the practical development of the lithium-sulfur battery, such us: (i) thelow 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 aresoluble in the organic electrolyte, thus producing a loss of active material inthe cathode, (iv) soluble polysulfides can be deposited on the anode surfacegiving rise to corrosion problems and an increase in the internal resistance ofthe cell with its consequent loss in charge-discharge capacity [5].In thiscontribution we present the preparation and characterization of manganese oxide[6] as additive for cathodes materials in lithium-sulfur batteries. Manganeseoxide was synthesized by oxidation of manganese carbonate and its subsequentselective removal with hydrochloric acid. The cathode material was synthesizedby 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 electrodeswere made by coating of a slurry mix on an aluminum current collector, thendried and pressed. The slurry mix was prepared with 80 wt% of the activematerial powder (S) and 10 wt% conductive additive powder (Super P carbon) withthe 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 andelectrochemical impedance spectroscopy.