Preparation of polyelectrolyte based on bottle brush Polyethylene glycol-Poly(N-isopropylacrylamide) copolymers

The increased demand for high energy-density batteries led to using lithium metal (Li) anode. However, safety issues associated with Li anode encouraged the researchers to use less reactive and safer electrolytes with higher electrochemical stability. High ionic conductivity (sigma), wider electrochemical stability window, and higher mechanical strength alongside the ability to self-heal possible structural damages were at the center of focus for developing efficient solid electrolytes. In this regard, we developed a group of solid polymer electrolytes (SPEs) with high sigma and electrochemical stability. In this regard, bottle brush polyethylene glycol (bbPEG) was synthesized using a chain transfer reaction. Polynipaam (PNIPAAM) blocks were also incorporated into the structure to prepare a block copolymer based on PNIPAM-bbPEG-PNIMAM represented by the ABA structure. The block copolymer was then blended with polyvinylidene fluoride (PVDF) with the block copolymer to PVDF weight ratio of 7:2% and 25% bis(trifluoromethane) sulfonamide (TFSI) salt was added and the final mixture was UV-cured. The results indicated that the final SPE possessed high ionic conductivity with a relatively high lithium-ion transference number (tLi+$$ {t}_{Li+} $$) of 0.416 and the sigma of 1.265 x 10-5 S/cm at 25 degrees C.