1. Asymmetric SO3CF3--Grafted Boron-Center Anion Enables Boron-Containing Interphase for High-Performance Rechargeable Mg Batteries.
- Author
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Xueting Huang, Shuangshuang Tan, Jinlong Chen, Ziwei Que, Rongrui Deng, Juncai Long, Fangyu Xiong, Guangsheng Huang, Xiaoyuan Zhou, Lingjie Li, Jingfeng Wang, Liqiang Mai *, and Fusheng Pan
- Subjects
STORAGE batteries ,MAGNESIUM ions ,LITHIUM cells ,SECONDARY ion mass spectrometry ,MAGNESIUM ,ELECTROSPRAY ionization mass spectrometry ,BORON steel - Abstract
Mg(SO
3 CF3 )2 (Mg(OTf)2 ) is a simple and cost-effective magnesium salt, which can promote the future applications of rechargeable magnesium batteries (RMBs). However, the simple Mg(OTf)2 /ether electrolytes suffer from poor electrochemical properties due to the low solubility of Mg(OTf)2 and the serious decomposition passivation of the [Mg2+ -OTf- ] ion pair on Mg. Herein, the OTf[sup -] anion is successfully grafted on low-cost fluoride boronic esters (B(OCx Hy F2x-y+1 )3 ) to obtain the asymmetric and weak-coordination boron-center [B(OCx Hy F2x-y+1 )3 OTf]- anion in ether electrolytes. The -OCH2 CF3 (TFE) groups in B(TFE)3 effectively realize the charge delocalization of the OTf[sup -]and B-O plane, restraining the independent decomposition of the [Mg2+ -OTf[sup -]] ion pair. The co-decomposition of the asymmetric [B(TFE)3 OTf]-induces the formation of the B-containing organic/inorganic interphase, thus achieving a reversible Mg plating/stripping. After the further solubilization reaction, the obtained electrolyte exhibits a high average coulombic efficiency of 98.13% and long-term cycling stability (1000 h). Notably, the long cycling life (capacity retention of 90.2% after 600 cycles at 1 C) and high-rate capacity (43.0 mAh g-1 at 5 C) of the Mg/Mo6 S8 full cell demonstrate a favorable electrolyte/cathode compatibility. This work brings new insights to design the new-type and low-cost Mg-salts and high-performance electrolytes for commercial RMBs. [ABSTRACT FROM AUTHOR]- Published
- 2024
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