Enhancing the performance of poly(ethylene oxide) solid electrolytes through synergistic interaction of starch and butanedinitrile

Abstract Solid polymer electrolyte (SPE) is one of the key materials being researched as the core component of all‐solid‐state lithium batteries, which are safer and helpful for higher energy densities. Although there has been extensive research, unifying electrochemical performance with environmental requirements is the new requirement of SPE. Here, natural and harmless starch is used as a filler to modify PEO‐based SPE, which are prepared using a simple solution casting method. Characterizations show that the electrochemical and mechanical properties of SPEs are both significantly improved through the interaction among PEO, starch and SN. The tensile strength increases by about 50%. The ionic conductivity reaches to 4.8 × 10 −5 S cm −1 at 30°C, with the Li + transfer number is 0.2 at 80°C. The electrochemical window of PEO/LiClO 4 /starch/SN SPE is about 5 V. For the Li/PEO/LiClO 4 /starch/SN SPE/Li symmetric cell, it gives stable lithium plating/stripping at 80°C for over 900 h at a current density of 0.1 mA cm −2 . These results provide a new idea for the green development of solid‐state electrolytes.