The calculated RDFs between the Li + ion and the carbonyl oxygen atoms of EC and DMC in the pure and IL/carbonate mixed solvent systems are presented in Figure . The calculated RDFs show the existence of a high intensity peak located at 2.17 Å for Li + -O 1 (DMC) coordination, and 2.32 Å for Li + -O 1 (EC) coordination. The presence of high amplitude peaks for both Li + -O 1 (DMC) and Li + -O 1 (EC) interactions indicates a strong interaction between the Li + ion and both DMC and EC molecules in the IL/carbonate mixture. For both Li + -O 1 (DMC) and Li + -O 1 (EC) interactions, the height of the peak increase in the order C 1 > D 1 > E 1 . Interestingly, it can be seen that the peak height for Li + -O 1 (EC) interactions is lower than for Li + -O 1 (DMC) interactions signifying the Li + -O 1 (DMC) interaction is greater than Li + -O 1 (EC) interaction in the IL/carbonate mixed electrlyic system. Further more, our results show that both Li + -O 1 (DMC) and Li + -O 1 (EC) interactions are more enhanced at higher EC/DMC carbonate contents (system C 1 ) than higher contents of [EMI][TFSI] contents (system E 1 ). In order to further investigate the effect of EC/DMC concentration on the ion association for [EMI][TFSI] electrolytes, the coordination of Li + ion with [TFSI] -anion was analyzed. In this study, we made distinctions between the number of anions coordinating with Li + ion, and the CN associated with this first solvation shell. The [TFSI] -anion has more than one bonding site for Li + ion, and in this case CN will be a greater number than the number of coordinating anions. For example, the cis and trans conformation of ). However, the sum of the average CN for pure IL content (system G 1 ) is 4.