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Formation of an artificial Mg2+-permeable interphase on mg anodes compatible with ether and carbonate electrolytes

DOI: 10.1021/acsami.0c22520 DOI Help

Authors: Yaqi Li (Harbin Institute of Technology; Diamond Light Source) , Pengjian Zuo (Harbin Institute of Technology) , Ruinan Li (Harbin Institute of Technology) , Hua Huo (Harbin Institute of Technology) , Yulin Ma (Harbin Institute of Technology) , Chunyu Du (Harbin Institute of Technology) , Yunzhi Gao (Harbin Institute of Technology) , Geping Yin (Harbin Institute of Technology) , Robert S Weatherup (University of Oxford; Diamond Light Source; Research Complex at Harwell; he Faraday Institution)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Materials & Interfaces

State: Published (Approved)
Published: May 2021
Diamond Proposal Number(s): 21925

Abstract: Rechargeable Mg-ion batteries typically suffer from either rapid passivation of the Mg anode or severe corrosion of the current collectors by halogens within the electrolyte, limiting their practical implementation. Here, we demonstrate the broadly applicable strategy of forming an artificial solid electrolyte interphase (a-SEI) layer on Mg to address these challenges. The a-SEI layer is formed by simply soaking Mg foil in a tetraethylene glycol dimethyl ether solution containing LiTFSI and AlCl3, with Fourier transform infrared and ultraviolet–visible spectroscopy measurements revealing spontaneous reaction with the Mg foil. The a-SEI is found to mitigate Mg passivation in Mg(TFSI)2/DME electrolytes with symmetric cells exhibiting overpotentials that are 2 V lower compared to when the a-SEI is not present. This approach is extended to Mg(ClO4)2/DME and Mg(TFSI)2/PC electrolytes to achieve reversible Mg plating and stripping, which is not achieved with bare electrodes. The interfacial resistance of the cells with a-SEI protected Mg is found to be two orders of magnitude lower than that with bare Mg in all three of the electrolytes, indicating the formation of an effective Mg-ion transporting interfacial structure. X-ray absorption and photoemission spectroscopy measurements show that the a-SEI contains minimal MgCO3, MgO, Mg(OH)2, and TFSI–, while being rich in MgCl2, MgF2, and MgS, when compared to the passivation layer formed on bare Mg in Mg(TFSI)2/DME.

Journal Keywords: magnesium batteries; TFSI− containing electrolyte; ether electrolyte; carbonate electrolyte; artificial SEI layer; passivation layer

Diamond Keywords: Batteries; Magnesium-ion

Subject Areas: Materials, Chemistry, Energy

Instruments: B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS

Discipline Tags:

Physical Chemistry Energy Energy Storage Material Sciences Energy Materials Physics Surfaces Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Photoelectron Spectroscopy (XPS) Near Edge X-ray Absorption Fine Structures (NEXAFS)