The
silicon-based anode has been regarded as the most competitive
anode candidate for next-generation lithium-ion batteries based on
its high theoretical specific capacity. However, the severe volume
expansion of the anode leads to undesirable cycling performance, hindering
its further application in full cells. In this work, a preactivation
method is carried out in a LiNi0.5Co0.2Mn0.3O2∥Si–graphite battery with an in situ gel electrolyte composed of carbonate solvents,
lithium hexafluorophosphate (LiPF6), β-cyanoethyl
ether of poly(vinyl alcohol) (PVA-CN), and additive lithium difluoro(oxalato)borate
(LiDFOB). After the charge–discharge test at ambient temperature
(300 cycles), the capacity retention of the battery with the in situ gel electrolyte (75.4%) is impressively promoted
compared with that with a base liquid electrolyte (45.7%). The in situ gelation and the strong solid electrolyte interphase
(SEI) film effectively suppress the volume expansion of the anode,
and the detected cathode transition metal elements on cycled anodes
sharply decline. At an elevated temperature (55 °C), the cycle
stability and Coulombic efficiency of the battery are also effectively
improved. Meanwhile, the battery owns good rate capability and low-temperature
performances similar to that with the liquid electrolyte. These results
would provide a feasible solution for applying in situ gel electrolytes in wide temperature range batteries with Si-based
anodes in practical applications.