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 CeO2 (Ca−CeO2) 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−CeO2). Our investigations demonstrate that the fluorous effect incurred by the fluorine-containing PEOA-PFPE and the oxygen vacancy effect induced by the Ca−CeO2 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−CeO2||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.