Synergy between partially exfoliated carbon nanotubes-sulfur cathode and nitrogen rich dual function interlayer for high performance lithium sulfur battery

Authors: Meenakshi Seshadhri Garapati, V.S. Ajay Piriya, Sundara Ramaprabhu – Carbon

DOI: doi.org/10.1016/j.carbon.2019.03.007

Abstract

Confinement of lithium polysulfides (LPS) within the cathode is one of the major challenges of LithiumSulfur Batteries (LiS), which hinders its practical application. Herein, a simple strategy is demonstrated to reduce the dissolution of LPS by graphitic carbon nitride nanosheets (GCN) supported by a gas diffusion layer (GDL), which consists of high nitrogen content, acts as polar sites for LPS adsorption. The partially exfoliated multi-walled carbon nanotube is used as a sulfur host (PECNT/S), which accommodates the high amount of sulfur loading due to its high specific surface area and pore volume. PECNT/S/GCN-GDL cathode remarkably exhibits excellent cyclic stability at 1C with 92.2% of initial capacity retention even after 500 cycles due to the strong trapping of LPS by chemisorption on GCN while the electrically conducting GDL ropes the electron conduction as well as electrolyte and Li+ ion diffusion. Dynamic electrochemical impedance spectroscopy technique further provides the understanding of confinement of LPS on the resultant PECNT/S/GCN-GDL electrode during charge-discharge processes. In addition, the importance of the upper potential limits has been studied in this work. Our study thus addresses many challenges of the LiS batteries by the use of carbon-based nanomaterials.

Download document