Repelling Polysulfides Using White Graphite Introduced Polymer Membrane as a Shielding Layer in Ambient Temperature Sodium Sulfur Battery

Herein, a strategy is demonstrated to effectively control the sodium polysulfide dissolution using composite polymer blend membrane. The sufficient interconnected pores in the white graphite introduced polymer blend membrane plays a multifunctional role as an ion selective membrane, evident from the ionic conductivity of 10−3 S cm−1 facilitating the movement of sodium ions and the presence of boron and nitrogen in white graphite acts as an effective absorbent to trap sodium polysulfides. The electrochemical testing reveals significant improvement of about 87.6% in specific capacity when compared to the cell without white graphite@ polymer membrane. Also, the cell exhibits an excellent cycling stability with a capacity retention of 83.1% at the end of 500 cycles. Other than the performance enhancement, the self-discharge battery is significantly reduced using the developed membrane. The better performance of the room temperature sodium sulfur battery is attributed to the physical and chemical confinement of composite polymer membrane which is also evident from the post analysis study. This is the first attempt of utilizing composite polymer membrane as a blocking layer in room temperature sodium sulfur batteries and is promising for the construction of high performance batteries.