Fluorinated polycarbonate-based solid electrolyte plasticized using succinonitrile for 4.5 V lithium metal batteries

Solid polymer electrolytes (SPEs) are a great promising choice for energy storage owing to their enhanced safety compared to liquid electrolytes. However, challenges such as the decomposition under the high voltage, low room-temperature ionic conductivity and poor room-temperature cycling performance have hindered the practical application of SPEs. In this study, SNSPE-40, a novel fluorinated polycarbonate-based electrolyte was prepared by the in-situ polymerization of 2,2,2-trifluoroethyl acrylate and 4-vinyl-1,3-dioxolan-2-one; succinonitrile was added to the electrolyte as a plasticizer. Notably, SNSPE-40 exhibits a high ionic conductivity of 1.33 mS cm-1 and wide electrochemical window of 5.4 V (vs. Li/Li+) at 25 degrees C. Due to the LiF-rich solid electrolyte interphase (SEI), the Li divided by SNSPE-40 divided by Li symmetric cell remained stable for 2000 h at 0.1 mA cm-2. Finally, the Li divided by SNSPE-40 divided by LiNi0.9Co0.05Mn0.05O2 cell, with a cut-off voltage of 4.5 V, displayed good cycling stability at 0.5 C (1 C = 220 mA g-1) and 26 degrees C (57.4% capacity retention after 300 cycles). The Li divided by SNSPE-40 divided by LiCoO2 cell displayed a long-cycling ability with a capacity retention of 54.9% for 250 cycles at 1 C (1 C = 200 mA g-1) under the same voltage and temperature conditions. This new solid polymer electrolyte shows great potential for the application in high-voltage solid-state lithium metal batteries. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(SPEs)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)SPEs(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)SNSPE-40. SNSPE-40(sic)25 degrees C(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)1.33 mS cm-1, (sic)(sic)(sic)(sic)(sic)(sic)(sic)5.4 V. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)SEI(sic)(sic)(sic)(sic), Li divided by SNSPE-40 divided by Li(sic)(sic)(sic)0.1 mA cm-2(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)2000 h. (sic)4.5 V(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), Li divided by SNSPE-40 divided by LiNi0.9Co0.05Mn0.05O2(sic)(sic)(sic)(sic)(sic)0.5C(1 C=220 mA g-1)(sic)(sic)300(sic)(sic)(sic)(sic)(sic)(sic)(57.4 % (sic)(sic)(sic)(sic)(sic)). Li divided by SNSPE - 40 divided by LiCoO2 (sic)(sic)(sic)(sic)(sic)1C(1C=200 mA g-1)(sic)(sic)250(sic)(sic)(sic)(sic)(sic)(54.9%(sic)(sic)(sic)(sic)(sic)). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).