Chem. J. Chinese Universities ›› 2024, Vol. 45 ›› Issue (5): 20240010.doi: 10.7503/cjcu20240010

• Physical Chemistry • Previous Articles     Next Articles

MgCl2-AlCl3-EMImBF4/Organic Ether for Rechargeable Magnesium Battery Electrolytes

WEN Jiaxin1(), YE Junliu1, WEI Xin2, YANG Jingdong1, YIN Xuejiao1, LI Lingjie3   

  1. 1.School of Architectural and Engineering,Chongqing Industry Polytechnic College,Chongqing 401120,China
    2.College of Materials Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China
    3.School of Chemistry and Chemical Engineering,Chongqing University,Chongqing 400044,China
  • Received:2024-01-07 Online:2024-05-10 Published:2024-03-29
  • Contact: WEN Jiaxin E-mail:18523976826@163.com
  • Supported by:
    the Science and Technology Research Program of Chongqing Municipal Education Commission, China(KJQN202103202);the Doctoral Research Foundation of Chongqing Industry Polytechnic College, China(2022GZYBSZK2-11)

Abstract:

Rechargeable magnesium batteries(RMBs) are considered to be one of the next most promising energy storage systems. The electrolyte has an important influence on the performance of RMBs. The RMBs electrolyte system of MACC-EMImBF4/organic ether(MACCE) was prepared by the addition of 1-ethyl-3-methyl-1H-imidazol-3-ium tetrafluoroborate(EMImBF4) into the magnesium aluminum chloride complex(MACC) electrolyte. The electrochemical performance and full cell performance of the MACCE electrolyte were tested by cyclic voltammetry(CV), linear scanning voltammetry(LSV), electrochemical impedance spectroscopy(EIS), and galvanostatic charge- discharge curves(GCD). The surface of the electrodes with MACCE electrolyte after circulation was analyzed by field emission scanning electron microscopy(FESEM), X-ray powder diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The results show that the addition of EMImBF4 can effectively improve the electrolyte performance, and the optimum molar ratios of MgCl2-AlCl3 to EMImBF4 is 5∶1. MACCE electrolyte has superior electrochemical performances with a high ionic conductivity(ca. 3.94 mS/cm), a low overpotential(ca. 59 mV), a high Coulombic efficiency(more than 97.5%), a high anodic stability[ca. 2.8 V(vs. Mg/Mg2+)], and a long-term(more than 500 h) cycling stability. The analysis results demonstrate that a nanoparticles layer can be formed on the surface of Mg anode during cycling, which is helpful to improve the cycling stability. Moreover, MACCE displays good compatibility with the Mo6S8 cathode material. The Mo6S8|MACCE|Mg full cell delivers a discharge specific capacity of 64.4 mA∙h/g(12.88 mA/g, 0.1C), which can retain ca. 73.2% even after 100 cycles. MACCE electrolyte is simple to be prepared, low cost, and can be applied to RMBs, which is of great significance to accelerate the commercial application of RMBs.

Key words: Rechargeable magnesium battery, Magnesium aluminum chloride complex(MACC) electrolyte, 1-Ethyl- 3-methyl-1H-imidazol-3-ium tetrafluoroborate, Electrochemical performance, Compatibility

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