In-situ preparation of chemically-crosslinked polyvinylpyrrolidone gel polymer electrolyte for lithium ion battery via room-temperature electron beam-induced gelation

In this research, we report an initiator-free and room-temperature 2.5 MeV electron beam (EB)-induced gelation strategy to in-situ create polyvinylpyrrolidone-based gel polymer electrolytes (PVP-GPEs) in a fully-assembled lithium ion battery (LIB). A radiation-sensitive liquid precursor consisting of 1-vinyl-2-pyrrolidone (VP), poly (ethylene glycol) diacrylate (PD), and LiClO4 liquid electrolyte (LE) was effectively converted to freestanding PVP-GPEs even at an absorbed dose of 2 kGy (Irradiation time of 6 s). The formed GPE at the absorbed dose of 2 kGy exhibited good thermal stability and mechanical integrity while providing good electrochemical oxidative stability (up to 4.7 V) and ion conductivity (2.03 × 10−3 S/cm at 25 °C). Moreover, the LiCoO2/PVP-GPE/graphite coin cell in-situ prepared at the absorbed dose of 2 kGy showed comparable retention capacity to that of an LE-based coin cell after 50 cycles. The findings of this study suggest that the proposed in-situ quick EB-induced gelation strategy (without use of an initiator and thermal treatment) could be a scalable way to allow high-throughput production of reasonably performing and safe LIBs.