Hybrid MgCl2/AlCl3/Mg(TFSI)2 Electrolytes in DME Enabling High-Rate Rechargeable Mg Batteries

Lanlan Yang; Chaoran Yang; Yawei Chen; Zhichen Pu; Zhenzhen Zhang; Yulin Jie; Xiang Zheng; Yunlong Xiao; Shuhong Jiao; Qi Li; Dongsheng Xu

doi:10.1021/acsami.1c07567

Hybrid MgCl₂/AlCl₃/Mg(TFSI)₂ Electrolytes in DME Enabling High-Rate Rechargeable Mg Batteries

ACS Appl Mater Interfaces. 2021 Jul 7;13(26):30712-30721. doi: 10.1021/acsami.1c07567. Epub 2021 Jun 22.

Authors

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Physical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.
² Hefei National Laboratory for Physical Science at the Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China.

PMID: 34156809
DOI: 10.1021/acsami.1c07567

Abstract

Rechargeable magnesium batteries (RMBs) are considered as one of the most promising next-generation secondary batteries due to their low cost, safety, dendrite-free nature, as well as high volumetric energy density. However, the lack of suitable cathode material and electrolyte is the greatest challenge facing practical RMBs. Herein, a hybrid electrolyte MgCl₂/AlCl₃/Mg(TFSI)₂ (MACT) in dimethyl ether (DME) is developed and exhibits excellent electrochemical performance. The high ionic conductivity (6.82 mS cm^-1) and unique solvation structure of [Mg₂(μ-Cl)₂(DME)₄]²⁺ promote the fast Mg kinetics and favorable thermodynamics in hybrid Mg salts and DME electrolyte, accelerating mass transport and the charge transfer process. Therefore, the great rate capability can be realized both in symmetric Mg/Mg cell and in CuS/Mg full cell.

Keywords: DME electrolyte; conductivity; rechargeable magnesium batteries; volumetric energy.