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Highly Efficient Multifunctional Interlayer for Lithium Sulfur Battery

Monday, 14 May 2018: 14:20
Room 609 (Washington State Convention Center)

ABSTRACT WITHDRAWN

Increase in the energy demands has attracted attention towards energy conversion and storage devices. Li ion batteries have played a major role in this aspect. The Li ion battery applications are limited portable electronic devices because of its low energy density and specific capacity. To overcome the limitation of LIB, high energy density batteries like Lithium Sulfur (LiS) batteries have gained more attention. The high abundance, low cost, high theoretical capacity (1675 mA h g-1) and high energy density (2600 Wh kg-1) of sulfur made it a comprising candidate for LiS battery. Although LiS battery is having very high energy density, but not yet commercialized due to its poor cycle life, and low coulombic efficiency. The major challenges of LiS are the dissolution of higher order polysulfides intermediates in the organic electrolyte. These higher order polysulfides migrate to the lithium metal anode and get reduced which leads to overcharging, accumulation of insulating sulfur on the anode and capacity fading. This mechanism is known as shuttle mechanism. On the other hand, the dissolution of polysulfides is also important, which provides the fresh sulfur available for the further reaction to takes place. Using a polysulfide trapping interlayer between cathode and separator can minimize the shuttle effect. This interlayer should highly either attractive or repulsive to polysulfides such that they cannot penetrate through it and migrate to anode. Sulfur (S) to polysulfides (Li2S) reduction happens in presence of the carbon, with high conductivity and high surface area. In the present work, a highly hydrophobic interlayer with high nitrogen content is designed, which can trap the intermediate polysulfides before they reach the anode. The use of partially exfoliated carbon nanotubes (PCNTs) as sulfur host can increase the reaction kinetics of the polysulfides with its high conductivity and surface area. The structural and morphological studies of the synthesized PCNTs sulfur composite (PCNTs/S) and nitrogen rich highly hydrophobic interlayer were done by X-ray diffraction (XRD) pattern, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The use of PCNTs/S cathode with nitrogen rich highly hydrophobic interlayer for LiS battery has shown excellent cyclic stability for more than 100 cycles at 1C (1C = 1675 mA g-1), high rate capability up to 2C and specific capacity more than 1000 mA h g-1 at 0.1C.