Porous polymer electrolytes for long-cycle stable quasi-solid-state magnesium batteries

The development of applicable electrolytes is the key point for high-performance rechargeable magnesium batteries (RMBs). The use of liquid electrolyte is prone to safety problems caused by liquid electrolyte leakage. Polymer-based gel electrolytes with high ionic conductivity, great flexibility, easy processing, and high safety have been studied by many scholars in recent years. In this work, a novel porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane is prepared by a phase inversion method. By immersing porous PVDF-HFP membranes in MgCl2-AlCl3/TEGDME (Tetraethylene glycol dimethyl ether) electrolytes, porous PVDF-HFP based electrolytes (PPEs) are formed. The PPE exhibits a high ionic conductivity (4.72 x 10(-4) S cm(-1), 25 degrees C), a high liquid electrolyte uptake of 162%, as well as a wide voltage window (3.1 V). The galvanostatic cycling test of Mg//Mg symmetric cell with PPE reveals that the reversible magnesium ion (Mg2+) plating/stripping occurs at low overpotentials (similar to 0.13 V). Excellent long cycle stability (65.5 mAh g(-1) over 1700 cycles) is achieved for the quasi-solid-state RMB assembled with MoS2/C cathode and Mg anode. Compared with the liquid electrolyte, the PPE could effectively reduce the side reactions and make Mg2+ plating/stripping more uniformly on the Mg electrode side. This strategy herein provides a new route to fabricate high-performance RMB through suitable cathode material and polymer electrolyte with excellent performance. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

This study focuses on the development of a novel porous PVDF-HFP membrane based electrolyte for high-performance rechargeable magnesium batteries. The electrolyte exhibits high ionic conductivity, excellent safety, and can enhance the cycling stability and performance of the battery.