Flexible and high performing polymer electrolytes obtained by UV-induced polymer–cellulose grafting

A novel UV-induced procedure, in the presence of glycidyl acrylate and proper radical/cationic photoinitiators, is here proposed to promote the in situ grafting of a methacrylic polymer network to the surface of natural cellulose fibers. As a result, composite polymer membranes reinforced by cellulose handsheets are obtained and demonstrate excellent mechanical features. The reactivity of the monomers is studied by FT-IR in real time measurements and the successful grafting is confirmed by surface spectroscopies. The polymer membranes prepared show high elastic modulus and tensile resistance and maintain high flexibility even after activation by swelling into a standard liquid electrolyte solution. The swelling procedure allowed us to obtain high ionic conductivity and remarkable electrochemical behavior when tested in laboratory scale lithium polymer cells. The system shows attractive features such as intrinsic safety, eco-compatibility, and low production cost and industrialization potentials, and is highly suitable for the rapidly expanding field of Li-based flexible batteries.