Polyaniline: an effective suppressor against diffusion and dissolution of polysulfides in Li-S battery

Abstract

To suppress the notorious shuttle effect and capacity fading in lithium-sulfur battery, polyaniline has been introduced due to its multi-anchoring sites for polysulfides, but high content of polyaniline is inevitably accompanied by increase in the inactive content of total cathode and sacrifice in the energy density. Here we disclose that extremely low polyaniline loading can realize excellent cell performance, where conductive polyaniline is uniformly produced on the surface of sulfur-wrapped carbon nanoparticles via dilute aniline polymerization. Even ca. 1 wt% of polyaniline loading is enough to suppress diffusion and dissolution of polysulfides, and the sluggish charge transfer is accelerated. In addition to enhanced cycle stability, a remarkable increase in capacity by ca. 46% is realized compared to sulfur-wrapped carbon composite after 100th at 0.5 C. Moreover, an electrochemical property with coulombic efficiency above 95% and a high capacity retention rate of 55% is achieved even after 500 cycles at ca. 2 wt% polyaniline loading.