To elucidate structural evolution of graphite cathode during the galvanostatic charge–discharge measurement, XRD pat- terns of graphite cathodes at different charging states were recorded. Charging graphite cathode induced splitting of orig- inal graphite (002) peak at 26.45into two new peaks located at 22–25and 30–35(Figure 3a), corresponding to the (00n) and (00n1) peak of graphite intercalation compounds. The appearance of the (00n1) peak is a clear sign of anion intercala- tion into graphite cathode.[10b] Based on formulas d00n Ic/n /(2sin00n) and d00n1 Ic/(n1) /(2sin00n1), stage infor-mation of graphite cathode can be calculated (Table S1, Sup- porting Information).[15] During the charge process, graphite cathode gradually transforms to a Stage 2 compound at the end of quasi-linear region (1.90–2.39 V), and further evolves to a Stage 1 structure after plateau region (2.39–2.44 V), and main- tains Stage 1 in the subsequent linear region (2.44–2.70 V). The charge stored in the linear region can be ascribed to a solid solution transition[15a] from dilute Stage 1 to dense Stage 1 struc- ture (Figure S11, Supporting Information). Upon discharging, the Stage number varies in a reverse way until recovery of unin- tercalated graphite. A mix stage structure (Stage-2 and Stage-3) was noticed at 1.9 V, which is associated with stage transition. The Raman spectra also corroborate anion intercalation into graphite cathode by the appearance of E2g2(b) mode (Figure 3b), which originates from symmetry variation of the boundary gra- phene layer and electronic effects of the intercalated anions.[16]Solid-state 19F nuclear magnetic resonance spectroscopy (NMR) was conducted to probe the intercalated species in the charged graphite. Before the measurement, graphite cathode was charged to 2.7 V (vs Zn/Zn2) at a current density of0.1 A g−1 and then rinsed with anhydrous dimethyl carbonate to remove the excess electrolyte. As shown in Figure 3c, the solid-state 19F NMR spectrum of charged graphite shows three broad signals at −68.3, −69.2, and −74.2 ppm, which indicate the presence of F-containing species in the charged graphite. In contrast, the spectrum of the hybrid electrolyte measured by solution-state NMR presents three sharp peaks at −72, −73.5, and −78.2 ppm, which originate from PF6−and TFSI−, respec- tively. The broadening of the lines arises from the restrictions in the tumbling motion of these ions in the graphite. The fact that the line observed only moderate narrows with increasing magic-angle-spinning (MAS) sample spinning implies a signifi- cant contribution from inhomogeneous broadening (disorder in the environment).