Solvated Structure of Hybrid Tetraglyme‐Aqueous Electrolyte Dissolving High‐Concentration LiTFSI‐LiFSI for Dual‐Ion Battery
Solvated Structure of Hybrid Tetraglyme‐Aqueous Electrolyte Dissolving High‐Concentration LiTFSI‐LiFSI for Dual‐Ion Battery
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用于双离子电池的高浓度LiTFSI-LiFSI混合四甘醇二甲醚-水电解质的溶剂化结构
DOI：
10.1002/cssc.202201805
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发表时间：
2022
期刊：
影响因子：
8.4
通讯作者：
Ishihara Tatsumi
中科院分区：
文献类型：
--
作者：
Yang Dengyao;Li Huan;Shen Xiaofeng;Watanabe Motonori;Ishihara Tatsumi
研究了高度浓缩的混合四甘醇二甲醚（G4）-水电解质的溶剂化结构，以提高KS 6使用的双离子电池的循环稳定性和性能。重量比为2：8的G4和水的混合溶剂能够溶解高达37 mol kg−1的9 LiFSI-1 LiTFSI支持盐（37 mol kg− 1G 2 W8）。 尽管支持盐的浓度如此高，但双离子电池在300次循环中仍表现出合理的充电和放电性能（放电容量为1040 mAh g-1，库仑效率为90%）。 这归因于通过添加G4将析氢反应（HER）电位降低至-1.05 V vs. Ag/AgCl。 傅里叶变换红外光谱、核磁共振和拉曼光谱表明，在混合G4-水电解质中，G4分子与Li+形成了更强的配位作用，形成了离子对[Li（G4）x（H2O）y]+配合物。在混合水溶液电解质中，证实了双（三氟甲磺酰基）酰亚胺（TFSI-）和双（氟磺酰基）酰亚胺（FSI-）共嵌入石墨碳KS 6阴极中。
The solvated structure of a highly concentrated hybrid tetraglyme (G4)‐water electrolyte was studied for an increasing cycle stability and performance of a KS6 used dual‐ion battery. Hybrid solvent of G4 and water with a weight ratio of 2 to 8 was able to dissolve 9LiFSI‐1LiTFSI supporting salts up to 37 mol kg−1(37 mol kg−1G2W8). In spite of such high concentration of supporting salts, reasonable charge and discharge performance of dual‐ion battery (discharge capacity of ≈40 mAh g−1and coulombic efficiency of 90 %) were exhibited over 300 cycles. This was attributed to the decreased hydrogen evolution reaction (HER) potential to −1.05 V vs. Ag/AgCl by addition of G4. From Fourier‐transform infrared, nuclear magnetic resonance, and Raman spectroscopies, G4 molecules were more strongly coordinated to Li+to form ion pairs of [Li(G4)x(H2O)y]+complex in hybrid G4‐water electrolyte. Co‐intercalation of bis(trifluoromethanesulfonyl)imide (TFSI−) and bis(fluorosulfonyl)imide (FSI−) into graphitic carbon KS6 cathode was confirmed in hybrid aqueous electrolyte.