Formation and investigation of properties of composite gel-polymer electrolytes based on Nafion@ZrO<sub>2</sub> membrane in Li<sup>+</sup> form

The use of cation-exchange membranes as polymer electrolytes in lithium metal batteries can inhibit dendrite formation during battery operation. Solvation of the membranes leads to an increase in ionic conductivity, but the mechanical properties, which also affect dendrite growth, are significantly degraded. In the present work, the mechanical strength and volumetric stability of Nafion®-117 membranes in Li+⁺ form solvated by a mixture of ethylene carbonate and propylene carbonate were improved by introducing nanosized zirconium dioxide particles into the membrane matrix by in situ method. It is shown that the introduction of 3.8 wt.% ZrO₂ leads to a ~28-fold increase in Young’s modulus compared to the unmodified membrane. At the same time, the volumetric stability of the membranes during solvation increases by ~3.4 times. However, the ionic conductivity of the membranes decreases after the introduction of dopant and is 3∙10–⁴, 5∙10–⁶ and 2.7∙10–⁶ S/cm at 25°C for the membrane without dopant and containing 3.8 wt.% and 6.7 wt.% zirconium dioxide, respectively.