3D Fiber Network Enhanced Composite Polymer Electrolytes for All-Solid-State Sodium Batteries

Abstract

All-solid-state sodium batteries (ASSBs) coupled with solid polymer electrolytes (SPEs) are considered a promising candidate for next generation energy-storage systems due to high energy-density, low-cost, and high-safety. However, the insufficient ionic conductivity and poor interfacial stability with Na metal anode of SPEs severely hinder their commercial applications. To tackle these issues, we designed a type of inorganic/polymer composite polymer electrolytes by dispersing the unique anion-trapping 3D fiber network with abundant Lewis-acid sites in the polymer matrix to realize ultra-stable ASSBs. The rich Lewis-acid sites exposed on the 3D fiber surface can grab anions to promote the dissociation of Na salts, thus significantly improve Na+ selective migrating ability. Meanwhile, the continuous channel formed between 3D fiber network and polymer matrix provides a fast Na+ transport path, further leading to high ionic conductivity. Importantly, the Na+ transference number can also be enhanced due to the anion-trapping effect, which will effectively limit anion migration, thus regulating Na+ concentration distribution for constructing stable electrolyte/Na anode interface. Based on such advantages, the resulting composite polymer electrolyte will simultaneously exhibit high ionic conductivity, considerable Na+ transference number, as well as enhanced interfacial stability toward Na metal anode. Consequently, the electrochemical properties, including discharge capacity, cycling stability, rate capability, and safety of all-solid state sodium batteries using these 3D fiber network enhanced composite polymer electrolytes will be remarkably improved. We believe that such a composite electrolyte design could provide an effective strategy for the construction of high safe and high energy-density all-solid-state rechargeable batteries. Figure 1