In-situ preparation of gel polymer electrolytes in a fully-assembled lithium ion battery through deeply-penetrating high-energy electron beam irradiation

•Electron beam (EB)-induced in-situ formation of PVCEA GPEs in the LIBs is developed.•The EB-based in-situ formation can be carried out in a short time without an initiator or thermal treatment.•The GPEs prepared in a nonwoven fabric exhibit comparable ionic conductivity to that of a LE.•Intimate integrity between the GPE and electrodes is achieved.•The GPE-based LIB shows comparable cycling performance to a LE-based LIB.