Composites of Sulfur-Titania Nanotubes Prepared by a Facile Solution Infiltration Route as Cathode Material in Lithium-Sulfur Battery

Abstract

Achieving high energy density has been the focus of research in rechargeable batteries. Lithiumsulfur system is attractive due to its high theoretical energy density (2500 Wh kg-1). The major problem in Li-S system is associated with the dissolution of lithium polysulfides formed at the cathode during discharge. Shuttling of polysulfides between the cathode and anode during cycling reduces the efficiency of cycling. In the present study, TiO2 nanotubes are prepared from nanoparticles by hydrothermal route. Titania-sulfur composite has been prepared by infiltrating sulfur solution into the TiO2 nanotubes and studied as a cathode material in a non-aqueous electrolyte. Cycling behavior of Li-S cells fabricated using pristine sulfur and TiO2 nanoparticle-sulfur composite is also studied for comparison. Cells with TiO2 nanotubes exhibit better discharge capacity and coulombic efficiency than the cells with TiO2 nanoparticles and pristine sulfur.

Dielectric Barrier Discharge (DBD) Plasma Coating of Sulfur for Mitigation of Capacity Fade in Lithium–Sulfur Batteries

“…They include complex time-consuming steps for solvent removal and are limited to small batches and laboratory-scale production. Many synthetic methods reported are multistep and complex, and they may need the use of autoclaves ,, or sealed-glass tubes or require the use of hazardous chemicals like HF , or high-power centrifugation. ,,− …”

“…The motivation behind this work was to ensure better electronic accessibility of sulfur (nanosized and within a conductive matrix) and trapping it in the matrix. In addition, other methods have been developed using mesoporous TiO 2 nanotubes, 18 mesoporous carbon spheres, 19 sulfur wrapped in graphene, 20 and embedded in reduced graphene oxide (rGO) 21 following a similar trend (trapping sulfur). The standard method of inserting sulfur in a porous rigid-host is the melting approach using the low melting point of sulfur and capillary adsorption as the driving force.…”

“…They include complex time-consuming steps for solvent removal and are limited to small batches and laboratory-scale production. Many synthetic methods reported are multistep and complex, and they may need the use of autoclaves 16,18,46 or sealed-glass tubes 47 or require the use of hazardous chemicals like HF 16,48 or highpower centrifugation. 25,26,49−52 Recently, the surface modification of flat surfaces (with the deposition of a conductive PEDOT thin film) was reported by polymerization of the 3,4-ethylene dioxythiophene (EDOT) under dielectric barrier discharge (DBD) plasma treatment.…”

Impact of Different Conductive Polymers on the Performance of the Sulfur Positive Electrode in Li–S Batteries

“…Nevertheless, attempts using the abovementioned strategies (on the preparation of core–shell type particles) always yield a large agglomerate, usually of hundreds of microns in size. In addition, the multistep synthesis methods are intricate; they may need the use of sealed-glass tubes or autoclaves or high-power centrifugation or require hazardous chemicals like hydrofluoric acid. ,,, Last but not least, these processes are time- and energy-consuming, and sulfur is lost by sublimation during the required heat treatment steps, rendering these strategies inadequate for practical upscaled applications. ,− Hence, the development of simple techniques to prepare conductive polymer-coated sulfur particles without heat treatment is of technological and economical interest. To the best of our knowledge, there are very limited reports on the conductive polymer-coated sulfur particles without heat treatment and/or their use in Li–S batteries.…”

“…9−11 In addition, impressive progress has been reported during the last few decades, focusing on the advancement of sulfur positive electrodes. 12,13 Different methods have been developed by using layered porous carbon, carbon nanofibers/nanotubes, 14,15 hollow carbon spheres, 16,17 and graphene. 18,19 However, in comparison with the rest, surface modification by coating is considered an impactful approach to enhance the electrical conductivity and prevent the dissolution of lithium polysulfides and for improving the electrochemical performance of positive electrode materials in the Li−S battery system.…”