119th General Meeting of the KCS

Type Symposium
Area Recent Trends in Electrochemistry I
Room No. 406호
Time THU 14:20-:
Code ELEC1-3
Subject Conditioning-free magnesium chloride-complex electrolyte for rechargeable magnesium batteries
Authors 오시형
한국과학기술연구원(KIST) 에너지융합연구단, Korea
Abstract The development of new battery systems beyond Li-ion is a hot topic world-wide, reflecting a rapidly expanding market for EVs and commercial large-scale ESS for load-leveling or emergency backup power. Rechargeable magnesium batteries have been proposed as a promising alternative to Li-ion since as a negative electrode material, magnesium has a high gravimetric and volumetric capacity and a low standard reduction potential of -2.372 V. Furthermore, magnesium is naturally abundant in the earth’s crust and thus magnesium batteries can be potentially manufactured at lower cost. One of the most critical challenges for this system is development of an electrolyte system which possesses a wide electrochemical window, while maintaining reversibility for Mg plating-stripping on the negative electrode. Recently, Aurbach et al. proposed a highly stable electrolyte called MACC, which consists of all inorganic species and is stable over 3.0 V. Although the precise nature of speciation is yet undefined, this electrolyte needs a complex activation process called ‘electrolytic conditioning’ involving up to a hundred cycles before use. We report a MACC-related electrolyte which does not require this complex electrolytic conditioning. Its simple one-pot synthesis was accomplished by the dissolution of magnesium metal in AlCl3/THF solution using CrCl3 as a promoter. We further demonstrate that this electrolyte functions well in the prototype cell consisting of Mo6S8 and Mg as positive and negative electrode, respectively. We also show that the employment of an ionic-liquid co-additive further extends the stability window. The crucial advantage originates from the very high Mg to Al ratio in the new electrolyte “MaCC”, which promotes 100% coulombic efficiency for Mg in the first cycle.
E-mail sho74@kist.re.kr