Trapping polysulfides by chemical adsorption barrier of LixLayTiO3 for enhanced performance in lithium-sulfur batteries

摘要

Lithium sulfur batteries are one of the most potential rechargeable energy storage devices due to its high energy density and low cost. Nevertheless, the practical applications are heavily hindered by polysulfide shuttle effect, which would cause fast capacity fading. Polysulfide adsorption has been proved to be an effective strategy via chemical bonding or physical constraint. Here, a fresh LixLayTiO3 and acetylene black hybrid coated separator was constructed to suppress the migration of polysulfides and served as an upper current collector to fully utilize the active material. The acetylene black embellished separator and the pristine one were used as reference. Comprehensive and systematic results proved that the hybrid coated separator could not only effectively trap polysulfides, but also promote the conversion of polysulfides, which would improve the rate and cycle performance. The as-prepared sample with 1.0% Li-x- LayTiO3 addition showed the best electrochemical performance with a high capacity of 890 mA h g(-1) at 1600 mAg(-1). An enhanced cycling performance with 716 mA h g(-1) retained after 100 cycles at 800 mA g(-1) was observed, corresponding to a capacity retention of 81.2%. In summary, this study provides a simple, low cost and effective approach to promote the development of lithium sulfur batteries. (C)( 2018 Elsevier Ltd. All rights reserved.