A multi functional binder with lithium ion conductive polymer and polysulfide absorbents to improve cycleability of lithium–sulfur batteries

• Published in: Journal of power sources 2015-10, Vol.294, p.187-192
• Main Authors: Li, Gaoran, Cai, Wenlong, Liu, Binhong, Li, Zhoupeng
• Format: Article
• Language: English
• Subjects: Cycleability; Functional binder; Lithiated Nafion; Lithium-sulfur battery; Nano-silica impregnation; Polymer blend
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.06.083

A Li–S battery with enhanced cycleability is developed using a multi-functional binder with cation-conductive polymer and polysulfide absorbents. The binder is composed of Li+-Nafion, polyvinylpyrrolidone, and nano silica. Macroporous carbon (MPC) is employed for sulfur retention in cathode. The multi-functional binder regulates tetrasulfide movement only in MPC pores during lithiation and delithiation cycling. The resultant Li–S battery shows excellent performance in discharge capacity and rate cycleability. The sulfur lithiation capacity reaches 1373 mAh g−1 at 0.2C (0.335 A g−1 of S) and 470 mAh g−1 at 5C (8.375 A g−1 of S). A rate capacity as high as 809 mAh g−1 has been achieved after 300 cycles at 1C charge–discharge rate. The Li–S battery showed very low capacity degradation rate of 0.08% per cycle at 1C rate. [Display omitted] •Polysulfides with long chain show insignificant shuttle in Li–S battery.•Existence of Li2S6 in macroporous carbon (MPC) promotes kinetic properties.•SiO2-impregnated polymer blend of Li+-Nafion with PVP as a binder is developed.•The developed binder regulates tetrasulfide movement only in MPC pores.•Resultant Li–S battery has low capacity degradation rate at 1C rate.