In the field of lithium ion batteries, two critical factors that drive research are energy density and safety. The formation of lithium dendrites during charging has limited the development of new battery technologies. Understanding the factors affecting the lithium dendrite growth could enable successful implementation of lithium metal anodes. One approach to mitigating dendrite growth is increasing the modulus of the electrolyte.  Solid polymer-based electrolytes have been shown to significantly reduce the nucleation and growth of protrusions during cycling. In my talk I will demonstrate two different ways of quantifying the rigidity of polymer electrolytes by studying shear modulus and yield stress. I will further demonstrate the effect of these two parameters in the battery performance.