Electrochemical Properties of Sulfurized-Polyacrylonitrile Cathode for Lithium-Sulfur Batteries: Effect of Polyacrylic Acid Binder and Fluoroethylene Carbonate Additive.

Sulfurized carbonized polyacrylonitrile (S-CPAN) is a promising cathode material for Li-S batteries owing to the absence of polysulfide dissolution phenomena in the electrolyte solutions and thus the lack of a detrimental shuttle mechanism. However, challenges remain in achieving high performance at practical loading because of large volume expansion of S-CPAN electrodes and lithium anode degradation at high current densities. To mitigate this problem, we propose a novel cell design including poly(acrylic acid) (PAA) binder for improved integrity of the composite electrodes and fluoroethylene carbonate (FEC) as additive in the electrolyte solutions for stabilizing the lithium metal surface. As a result, these cells delivered high initial discharge capacity of 1500 mAh g-1 and a superior cycling stability ∼98.5% capacity retention after 100 cycles, 0.5 C rate, and high sulfur loading of 3.0 mg cm-2. Scaled-up 260 mAh pouch cells are working very well, highlighting the practical importance of this work.