A porous gel-type composite membrane reinforced by nonwoven: promising polymer electrolyte with high performance for sodium ion batteries

A porous composite membrane with P(VDF-HFP) as host and nonwoven as reinforcement has been successfully prepared and reported in this paper. The tensile strength of the composite is very close to that of Celgard 2730 separator in both wet and dry state. The Na⁺ ionic conductivity of the given gel-type composite membrane (0.82 mS cm⁻¹) absorbed NaClO₄ organic liquid electrolyte at room temperature has found to be four times higher than that of the commercial separator saturated with the same electrolyte (0.16 mS cm⁻¹). It has also showed enhanced transference number of Na⁺ ions and good electrolyte retention even at 110 °C. The electrochemical reversibility for Na₄Mn₉O₈ cathode has been confirmed by cyclic voltammetry by using the aforementioned gel polymer electrolyte (GPE). The porous composite GPE exhibits great application prospect for sodium ion batteries with high energy density.