An atomic level analysis of conductivity and strength in poly(ethylene oxide) sulfonic acid-based solid polymer electrolytes

The structure, ionic conductivity and strength of poly(ethylene oxide) (PEO) sulfonic acid-based solid polymer electrolytes with various contents of the PEO polymer are analyzed using molecular dynamics simulations. To quantify the electrolyte structure, comprehensive coordination and dimensional analyses are carried out. Ionic conductivity is determined by computing the Einstein-diffusion based conductivity for all ionic particles in the system. The strength of the electrolyte is quantified by carrying out a set of molecular simulations of the uniaxial deformation process under constant stress-rate conditions. The results obtained indicate that increased hydration improves the ionic conductivity, but degrades the strength in solid polymer electrolytes at hand. In addition, it appears that there is an optimal level of the PEO polymer content in these materials, which at the same hydration level, yields the best combination of ionic conductivity and strength.