Designing Low‐Concentration Propylene Carbonate‐based Electrolyte by Manipulating Lithium+‐Solvation Structure for Graphite Anode

Abstract We systematically study the correlation between Li + ‐solvation structure, interfacial stability, and electrochemical behavior in the system of graphite anode with low‐concentration (0.5 M) propylene carbonate (PC)‐based electrolyte (LCPE). 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropylether (TTE) [or 1,1,2,2‐tetrafluoroethyl‐2,2,2‐trifluoroethyl ether (HFE)] is used to manipulate the solvation structures of Li + in the LCPEs. Varying Li + ‐solvation structures are realized by changing the volume ratios of PC to TTE (or HFE) in the LCPEs. With the increase of TTE (or HFE) dosages, the relative contents of LiF and Li x PO y F z in SEI derived from increase, while the decomposition products of PC reduce. With enough TTE (or HFE) in the LCPE, the Li||graphite cell exhibits reversible (de)lithiation without PC co‐intercalation and continuous electrolyte decomposition due to the shield of a compact SEI rich in LiF and Li x PO y F z . Our work proves it is practicable to achieve LiF‐riched SEIs on graphite anodes and realize reversible (de)lithiation in LCPEs by regulating the Li + ‐solvation structures with inert cosolvents.