Poly(ethylene glycol) (PEG)-crosslinked poly(vinyl pyridine)-PEG-poly(vinyl pyridine)-based triblock copolymers prepared by RAFT polymerization as novel gel polymer electrolytes

A series of triblock copolymers based on poly(vinyl pyridine)-PEG-poly(vinyl pyridine) (PVP-PEG-PVP) with different PEG-to-PVP ratios (1:200, 1:250, and 1:500) were prepared using the RAFT polymerization method and further crosslinked with PEG to produce PEG-crosslinked PVP-PEG-PVP triblock copolymers as novel gel polymer electrolytes. The nanostructured morphologies were controlled using the triblock copolymer structure and PEG was introduced both as a Li ion conductor and as a crosslinker on the side chain of the PVP. The resulting PEG-crosslinked PVP-PEG-PVP gel polymer electrolytes showed good thermomechanical properties, together with moderate ionic conductivities exceeding 1.34 x 10(-5) S cm(-1) at 25 degrees C and 2.94 x 10(-4) S cm(-1) at 80 degrees C. The good ionic conductivity and mechanical stability of these newly developed gel polymer electrolytes ensured a high capacity (135 mA h g(-1) at the 30(th) cycle and a retention of 94.4% of the initial capacity) in a Li battery prepared using the PEG-crosslinked triblock (1:200)-based electrolyte films.