In-Situ Crosslinked Single-Ion Conducting Gel Polymer Electrolyte for Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) have been considered as promising candidates for energy storage device due to their high energy density. However, high reactivity of lithium metal with liquid electrolyte and continuous growth of dendrite lead to degradation of cycle performance and cell failure. To overcome these problems, the strategy of employing gel polymer electrolytes (GPE) was investigated. GPE can effectively encapsulate organic solvents and facilitate uniform contact with electrodes. Both cations and anions migrate in conventional GPE, which gives rise to low Li+ ion transference number (tLi+). Low tLi+ causes inhomogeneous Li+ ion flux and continuous dendrite growth. Compared to conventional GPE, single-ion conducting gel polymer electrolytes (SIC-GPE) have superior tLi+ value close to unity, since the movement of anions is suppressed. In this work, we synthesized a novel sulfonamide based single-ion conductor and prepared the chemically crosslinked SIC-GPE. The electrolyte was obtained by a facile in-situ crosslinking that further improves interfacial contact with electrodes. The resulting SIC-GPE exhibited high tLi+, which led to homogeneous deposition of Li+ ion and enhanced electrochemical stability. The LMB cell employing SIC-GPE exhibited stable cycle performance, proving ability to suppress the growth of lithium dendrite.