Multifunctional Nanocomposite Polymer‐integrated Ca‐doped CeO₂ Electrolyte for Robust and High‐rate All‐solid‐state Sodium‐ion Batteries

Abstract Due to the seamless interfaces between solid polymer electrolytes (SPEs) and electrode materials, SPEs‐based all‐solid‐state sodium‐ion batteries (ASSSIBs) are considered promising energy storage systems. However, the sluggish Na + transport and uncontrollable Na dendrite propagation still hinder the practical application of SPEs‐based ASSSIBs. Herein, Ca‐doped CeO 2 (Ca−CeO 2 ) nanotube framework is synthesized and integrated with poly (ethylene oxide) methyl ether acrylate‐perfluoropolyether copolymer (PEOA‐PFPE), resulting in multifunctional solid nanocomposite electrolytes (namely SNEs, i.e., PEOA‐PFPE/Ca−CeO 2 ). Our investigations demonstrate that the fluorous effect incurred by the fluorine‐containing PEOA‐PFPE and the oxygen vacancy effect induced by the Ca−CeO 2 framework could synergistically promote the dissociation of sodium salt, ultimately enhancing the Na + mobility in SNEs. Besides, the resultant SNEs construct rapid Na + transport channels and homogenize the Na deposition in SNEs/Na interface, which effectively prevents the Na dendrite growth. Furthermore, the assembled carbon‐coated sodium vanadium phosphate (NVP@C)||PEOA‐PFPE/Ca−CeO 2 ||Na coin cell delivers impressive rate capability of 97.9 mAh g −1 at 2 C and outstanding cycling stability with capacity retention of 84.3 % after 300 cycles at 1 C. This work illustrates that constructing multifunctional SNEs via incorporating functional inorganic frameworks into fluorine‐containing SPEs could be a promising strategy for the commercialization of robust and high‐performance ASSSIBs.