Selenium containing Tube-in-Tube carbon: A one dimensional carbon frame work for selenium cathode in Li-Se battery

MWCNT encapsulated by highly porous carbon, also called as Tube-in-Tube carbon (TTC), obtained from hard template assisted synthesis method acts as an efficient host for Se cathode in Li-Se battery. One dimensional nano structured TTC with a high pore volume of 2.167 cc/g and an appreciable surface area of 1131 m2/g is capable of accommodating as high as 70 wt% Se. Notably, 50 wt% Se@TTC delivers an initial capacity of 625 mAh/g at C/5 rate and an acceptable progressive capacity of 403 mAh/g up to 800 cycles. Further, 55% of the initial capacity is retained up to 800 cycles under 2C rate. It exhibits 254 mAh/g at 10C rate and an insignificant decay of 0.01% per cycle at 1C rate for 4000 cycles. On the other hand, 60 wt% Se@TTC exhibits superior capacity behaviour than 50 wt%. Se loaded cathode up to 3C rate and a moderate capacity of 190 mAh/g at 10C rate. Based on the demonstration of excellent cycleability, superior reversibility and rate capability, TTC is recommended as a promising host for Se cathode in Li-Se batteries. The encouraging electrochemical performance of Se@TTC could be attributed to the synergistic effect of MWCNT and porous nature of carbon.

523