Lithium-ion batteries have emerged as the main technology in electrical energy storage due to their high energy density and long cycle life. However, the traditional liquid electrolytes used in Li-ion batteries still present significant safety concerns, including the risk of leakage, flammability, and thermal instability. Solid polymer electrolytes offer a promising alternative as their higher electrochemical stability, mechanical flexibility, ease of fabrication, and high property tunability could enhance the overall performance and safety of Li-ion and pave the way for Li-metal batteries. On the downside, polymer electrolytes suffer from low room-temperature ionic conductivity due to low solubility of lithium salts in polymers, and limited chain dynamics to facilitate ion conduction. Low transference number is a common limitation of polymer electrolytes, which leads to concentration gradients that decrease battery performance at high current density. The majority of the work on polymer electrolytes has concentrated on Poly(ethylene oxide) (PEO), and while other systems such as polynitriles, carbonyls, and single ion conductors have been proposed, none have reached ionic conductivity on par with liquid electrolytes at room temperature. Molecular dynamics (MD) simulations have been used to investigate diffusion mechanisms and structural properties in polymer electrolytes. Insights into Li diffusion mechanisms, ion clustering, ion correlated motion, the negative transference number phenomenon, and solvation behavior of PEO have all been explored with the help of MD simulations. Various works have investigated the solvation structure of Li in a PEO matrix and found coordination numbers for Li between 4 and 8, depending on the selected cutoff distance and modeling choices. PEO with Li bis(trifluoromethanesulfonyl)imide (TFSI) as the salt represents the overwhelming majority of computational research in this field, creating a lack of comparisons of structural and dynamical properties across polymer and salt chemistries.