Cellulose-Derived Flame-Retardant Solid Polymer Electrolyte for Lithium-Ion Batteries

The evolution of electric vehicles and advanced wearable flexible devices is closely bound with battery safety. Herein, we report, a synthesis of thermally stable, flame-retardant, and flexible solid polymer electrolyte using eco-friendly materials such as cellulose triacetate, PEGMA, and ionic liquid PYR14TFSI. PYR14TFSI and salt LiTFSI were added to the polymer to make a solid polymer electrolyte (PCIL). The conductivity of PCIL at normal temperatures is observed to be 5.24 X 10(-3 )S cm(-1), which further increased to 1.03 X 10(-2) S cm(-1) at 70 degrees C. An average transference number (t+) of about 0.43 has been observed for PCIL, which is much better than that for the liquid electrolyte. Moreover, PCIL, being highly stable up to 5 V, can be employed in high-voltage applications. The half cell with LFP as cathode displays the 1st discharge capacity of 125 mAh g(-1) at room temperature. It's interesting to note that, after 50 cycles, the cell retains an initial discharge capacity of 76% at room temperature. Additionally, electrospun derived carbon exhibits first discharge capacity at 340 mAh g(-1) which reduced to 216 mAh g(-1) after 40 cycles. It should be noted that these cycling studies were carried out at ambient temperature, and it was also noted that the synergic effect of polymeric and ionic liquid systems at higher temperatures leads to an increase in mobility of charge carriers, which ultimately confers easier ionic transport and improved storage capacity. The present SPE PCIL may have potential in high-voltage LIBs.