Authors: Girish Salian1, Jonathan Højberg2, Reza Younesi1
Title: Capacity fade mechanisms in LiNi0.5Mn1.5O4 based cells
Affiliation: 1Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala, Sweden. 2Haldor Topsøe A/S, Haldor Topsøes Allé 1, DK-2800 Kgs. Lyngby, Denmark
Due to its high operating voltage and theoretical capacity of 147 mAh/g, LiNi0.5Mn1.5O4 (LNMO) renders a high theoretical energy density of 690 Wh/kg. This is because of Ni2+/Ni4+ redox couple with a voltage plateau at 4.7 V (vs. Li/Li+). Additionally, the excellent rate capabilities of LNMO makes it ideal for high-power applications. However, due to high voltage operation, the instability of conventional electrolytes (aprotic carbonates with LiPF6 salt) causes interfacial reactions accompanied by transition metal dissolution, especially at elevated temperatures, leading to rapid capacity fading. To address the above given issues, EC (ethylene carbonate)-free electrolytes could be employed since EC based electrolytes experience poor stabilities at higher potentials.
We will present our latest results on studying EC-free electrolytes for LNMO based cells. Electrochemical measurements of LNMO based cells, in which different types of counter-electrodes were used, will be discussed.