A non-nucleophilic gel polymer magnesium electrolyte compatible with sulfur cathode

摘要

Magnesium/sulfur battery(Mg/S)has recently received wide attention due to its high theoretical energy density(3,260 Wh/L)and low cost.To further improve its safety and flexibility,developing a polymer electrolyte that can be compatible with both electrophilic S and Mg is critical.Here,we report a magnesium chloride-(fluorinated tetraethylene glycolic)borate(MgCl-FTGB)based non-nucleophilic,gel-type polymer electrolyte for Mg/S battery via a facile synthetic method through commercially available reagents.This electrolyte coupled with glass fiber allows reversible Mg deposition/dissolution(100%coulombic efficiency)with low polarization(500μA/cm^2,300/300 mV),and shows a wide electrochemical window of 4.8 V(vs.Mg/Mg^2+).Mg/S battery assembled with this electrolyte can cycle over 50 times with a high specific discharge capacity retention of over 1,100 mAh/g.