Gel Polymer Electrolyte with High Li⁺ Transference Number Enhancing the Cycling Stability of Lithium Anodes

Abstract

Lithium anodes suffer from severe safety problems in liquid electrolyte systems that result from an unstable Li plating/stripping process and Li dendrite growth, leading to rapid degradation of Li metal batteries. A polyethylene (PE)-supported gel polymer electrolyte (GPE) with excellent electrolyte uptake/retention capability was simply prepared in this paper by the construction of cross-linked polymer networks (PNs) on the surface of a poly(ethylenimine)-primed PE separator to stabilize the lithium anode. The highly delocalized negative charge of p-styrene sulfonate groups on PNs plays a role in regulating the Li⁺ and anion transport, giving rise to a high Li⁺ transference number. This GPE extended the electrochemical stability to 4.8 V and improved the stability of interface between the electrolyte and lithium metal anode (reduced overpotential and suppressed lithium dendrites) during storage and repeated lithium plating/stripping cycling. The Li metal anode-based battery employing this GPE exhibits excellent cycling stability and C-rate capability.