Starch Acetate Grafted to MXene Composite Surpasses Room Temperature Liquid Electrolyte Performance for All‐Solid‐State Lithium‐Ion Batteries

A groundbreaking solid polymer electrolyte (SPE) design is reported that outperforms traditional liquid electrolytes in both performance and safety, while being environmentally benign. By leveraging click chemistry, starch acetate (SA) is integrated, a natural polymer itself capable of supporting superionic conductivity, with MXene quantum dots (MX-QDs). While the composite electrolyte is electrically insulating, the electrical conductivity of the MXene stabilizes the anionic species while also acting as a filler to boost mechanical properties. The optimized SPE composition, comprising 30 wt.% MX-QDs, exhibits exceptional electrochemical characteristics: ionic conductivity of 14.8 mS cm^-1, lithium cation transfer number of 0.91, and an electrochemical stability window of up to 5.2 V. Notably, this SPE demonstrates seamless compatibility with lithium metal anodes, enabling a solid-state battery that retains 90% capacity over 1000 charge-discharge cycles. This innovative SPE design paves the way for the widespread adoption of solid-state batteries in electric vehicles.