TY - JOUR
T1 - Solvation-Structure Modification by Concentrating Mg(TFSA)2-MgCl2-Triglyme Ternary Electrolyte
AU - Shimokawa, Kohei
AU - Matsumoto, Hajime
AU - Ichitsubo, Tetsu
PY - 2018/8/16
Y1 - 2018/8/16
N2 - Mg(TFSA)2/triglyme(G3)-based electrolytes (TFSA: bis (trifluoromethanesulfonyl) amide) are one of candidates for magnesium rechargeable batteries, but the passivation of Mg-metal anode due to the TFSA anion is fatal in practical use. In this work we show that at elevated temperatures around 150 °C a comparable amount of MgCl2 salt can be dissolved in concentrated Mg(TFSA)2/G3 solutions, and the passivation of Mg metal is markedly suppressed in such highly concentrated solutions (1 ≤ G3/Mg-salts ≤ 2) in comparison with in the dilute solutions (G3/Mg-salts ≫ 2). By decreasing the amount of G3 solvent, the solvation structure of Mg2+ ions is modified in that free TFSA anions are drastically lowered, which would consequently decrease the reactivity of TFSA anions. We also demonstrate that a full-cell using MgCo2O4 cathode with the electrolyte of Mg(TFSA)2/MgCl2/G3 1:1:2 at 150 °C delivers a cell voltage of ∼2 V versus Mg-metal anode.
AB - Mg(TFSA)2/triglyme(G3)-based electrolytes (TFSA: bis (trifluoromethanesulfonyl) amide) are one of candidates for magnesium rechargeable batteries, but the passivation of Mg-metal anode due to the TFSA anion is fatal in practical use. In this work we show that at elevated temperatures around 150 °C a comparable amount of MgCl2 salt can be dissolved in concentrated Mg(TFSA)2/G3 solutions, and the passivation of Mg metal is markedly suppressed in such highly concentrated solutions (1 ≤ G3/Mg-salts ≤ 2) in comparison with in the dilute solutions (G3/Mg-salts ≫ 2). By decreasing the amount of G3 solvent, the solvation structure of Mg2+ ions is modified in that free TFSA anions are drastically lowered, which would consequently decrease the reactivity of TFSA anions. We also demonstrate that a full-cell using MgCo2O4 cathode with the electrolyte of Mg(TFSA)2/MgCl2/G3 1:1:2 at 150 °C delivers a cell voltage of ∼2 V versus Mg-metal anode.
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U2 - 10.1021/acs.jpclett.8b02209
DO - 10.1021/acs.jpclett.8b02209
M3 - Article
C2 - 30080047
AN - SCOPUS:85051802389
VL - 9
SP - 4732
EP - 4737
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 16
ER -