Expanded Graphite(EG)/ Chitosan(C) Coated Separators for Highly Stable Lithium Sulfur Batteries

Abstract

Lithium sulfur battery (LSB) has been considered as a promising candidate for next-generation energy storage systems, due to its high theoretical specific capacity (1675mAh/g). However, the poor cycling life hinders in its commercial production. The short cycling life results from continuous loss of active material in the form of lithium polysulfide’s during a typical charging and discharging process, commonly known as shuttling phenomenon. In this abstract i will discuss our unique approach of dual (physical, chemical) interaction mechanism based on EG/C coated separator to stop the lithium polysulfide shuttle. The light weight EG/C coated separator (0.13mgcm -2 ) can extend the cycling life of LSB to 3000 cycles at 1C-rate (1C= 1675mA/g) as shown in the figure below; reducing the decay rate to 0.02% per cycle which is among the best reported up to date. Live in-situ electrochemical discharging results shows that the modified separator works effectively in curbing the polysulfide shuttle. Flexible batteries based on modified separator were also fabricated and able to light up 4 parallel LED circuit. Figure 1