Natural abundance 17 O and 6 Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li + at various concentrations of LiFSI in DME electrolytes. It was found that the chemical shifts of both 17 O and 6 Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME) 2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li + and FSIion increases, but the association between Li + and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li + (FSI-) 2 (DME), Li + 2 (FSI-)(DME) 4 and (LiFSI) 2 (DME) 3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li + decreases, and the coordinated number of FSIincreases, which is in perfect accord with the DFT results.