Poly[poly(ethylene glycol) methacrylate]-modified starch-based solid and gel polymer electrolytes for high performance Li-ion batteries.

The idea of replacing liquid electrolytes with polymer electrolytes has been successful and the development of these electrolytes has provided acceptable results. With the start of using natural polymers in the polymer industry, as well as starch, these materials can be one of the most important candidates for the polymer matrix in electrolytes. In this study, starch has been investigated as a polymer electrolyte, poly[poly(ethylene glycol) methacrylate] (PEGMA) is grafted to the starch by radical polymerization, and synthesized copolymers are used as solid polymer electrolytes (SPEs). Furthermore, by adding N,N'-methylenebisacrylamide (MBA) as a cross-linking agent, gel polymer electrolytes (GPEs) are produced after swelling in the liquid electrolyte. After characterization, the synthesized polymer electrolytes are investigated in terms of electrochemical properties. The best ionic conductivity of 3.8 × 10-5 S cm-1 is obtained for SPEs whereas it is obtained 4.3 × 10-3 S cm-1 for GPEs at room temperature. The ion transfer number in the range of 0.47-0.91 confirms the compatibility between the electrolytes and electrode. Also, the prepared polymer electrolytes present excellent electrochemical properties, including, a wide electrochemical stability window above 4.7 V, good specific capacities in the range of 170-200 mAh g-1 with a storage capacity of more than 92 %, and Coulombic efficiency of about 98 % after 100 cycles at 0.2 C.