Parisa Shabani Nezhad, Prof. Junjie Niu* Core-Shell Structure of Sulfur-Polypyrrole for Lithium-Sulfur Batteries Parisa Shabani Nezhad, Prof. Junjie Niu*

Li-S vs. other cell chemistries

Challenges

Experimental

Result & discussion (a)TEM images of the S-polymer composite (b)Magnified image of a single sulfur−polymer core−shell particle (c)the corresponding EDX elemental mapping (d)EDX spectrum of composite.

Conclusion The uniform and flexible PPy layer helps to encapsulate and confine the sulfur/polysulfides physically inside the core–shell structure, thus alleviating the volume expansion of sulfur and polysulfide effects during the cycling. With PPy as a coating layer, the aggregation and growth of sulfur particles was also obviously avoided, which results in faster ion transfer. Moreover, PPy as a conductive polymer can partly enhance the electrical conductivity of sulfur particles.

References 1.Xie et al, “Facile large-scale synthesis of core–shell structured sulfur@polypyrrole composite and its application in lithium–sulfur batteries with high energy density”, Applied Energy 175 (2016), 522-528. 2. Zhou et al, “Yolk−Shell Structure of Polyaniline-Coated Sulfur for Lithium−Sulfur Batteries”, J. Am. Chem. Soc 135 (2013), 135 (44), 16736 16743. 3.Ni et al, “Core–Shell Structure and Interaction Mechanism of γ-MnO2 Coated Sulfur for Improved Lithium-Sulfur Batteries”, Small 13 (2017). 4.Niu et al, “Scalable synthesis of a sulfur nanosponge cathode for a lithium–sulfur battery with improved cyclability”, J. Mater. Chem. A (2014).