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

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. (C) 2015 Elsevier B.V. All rights reserved.