||Sodium ion batteries (SIBs) are one of the promising energy storage devices and are at the forefront as an alternative to lithium ion batteries (LIB). Liquid electrolytes composed of organic solvents and sodium salts are widely used with separators in SIB. Glass fiber (GF), a commercial separator for SIB generally used with organic electrolytes, exhibits high ion conductivity and suitable cell performance. However, safety issues from explosions can result from leakage and flammability of liquid electrolytes. Poly (vinylidene fluoride-co-hexa fluoropropylene) (PVdF-HFP) copolymers are often chosen as coating polymers in many substrates such as nonwovens and GFs to solve these problems. In this study, a structured gel-polymer electrolyte (SGPE) with controllable and optimized pore structure by a simple phase inversion method is introduced with its improved electrochemical stability and performance for sodium ion battery.