Nanocrystalline TiO2/Carbon/Sulfur Composite Cathodes for Lithium–Sulfur Battery

Abstract

This paper evaluates the influence of the morphology, surface area, and surface modification of carbonaceous additives on the performance of the corresponding cathode in a lithium–sulfur battery. The structure of sulfur composite cathodes with mesoporous carbon, activated carbon, and electrochemical carbon is studied by X-ray diffraction, nitrogen adsorption measurements, and Raman spectroscopy. The sulfur cathode containing electrochemical carbon with the specific surface area of 1606.6 m2 g−1 exhibits the best electrochemical performance and provides a charge capacity of almost 650 mAh g−1 in cyclic voltammetry at a 0.1 mV s−1 scan rate and up to 1300 mAh g−1 in galvanostatic chronopotentiometry at a 0.1 C rate. This excellent electrochemical behavior is ascribed to the high dispersity of electrochemical carbon, enabling a perfect encapsulation of sulfur. The surface modification of carbonaceous additives by TiO2 has a positive effect on the electrochemical performance of sulfur composites with mesoporous and activated carbons, but it causes a loss of dispersity and a consequent decrease of the charge capacity of the sulfur composite with electrochemical carbon. The composite of sulfur with TiO2-modified activated carbon exhibited the charge capacity of 393 mAh g−1 in cyclic voltammetry and up to 493 mAh g−1 in galvanostatic chronopotentiometry. The presence of an additional Sigracell carbon felt interlayer further improves the electrochemical performance of cells with activated carbon, electrochemical carbon, and nanocrystalline TiO2-modified activated carbon. This positive effect is most pronounced in the case of activated carbon modified by nanocrystalline TiO2. However, it is not boosted by additional coverage by TiO2 or SnO2, which is probably due to the blocking of pores.

Investigation and Design of High-Loading Sulfur Cathodes with a High-Performance Polysulfide Adsorbent for Electrochemically Stable Lithium–Sulfur Batteries

“…Moreover, high electrochemical utilization and stability must be ensured using a high-loading sulfur cathode . Therefore, simultaneously increasing the sulfur loading and content to more than 2.0 mg cm –2 and 60 wt %, respectively, remains a significant challenge. − ,− …”

“…To address the intrinsic material and extrinsic engineering issues of the lithium–sulfur technology, different porous carbon and functional polymer materials are often applied as the cathode additives with an additional amount of 10–30 wt % to inhibit the polysulfide diffusion and the derived redeposition of the insulating precipitates. − , To enhance the adsorption ability, researchers currently develop oxide-based cathodes that adopt metal oxides to immobilize and catalyze lithium polysulfides because of their strong covalent bonds toward polysulfide molecules and surface active sites for high electrocatalytic activity. Among the reported high-performance oxide-based cathodes, specifically, TiO 2 , ,− ZrO 2 , , SiO 2 , , ZnO, ,− and Al 2 O 3 − are probably to be the most commonly used foundations for investigating the strong chemical adsorption and fast conversion of the anchored polysulfides. However, the strong polysulfide adsorption effects of the oxide-based cathodes are often proven to have both physical confinement and chemical adsorption for an effective cathode design. − As a result, the previous success in the development of various oxide-based cathodes and the ambiguous contributions of the physical and chemical polysulfide-trapping capability reported in the literature inspire us to explore the chemical polysulfide adsorption capability of oxide materials.…”

“…Among the reported high-performance oxide-based cathodes, specifically, TiO 2 , ,− ZrO 2 , , SiO 2 , , ZnO, ,− and Al 2 O 3 − are probably to be the most commonly used foundations for investigating the strong chemical adsorption and fast conversion of the anchored polysulfides. However, the strong polysulfide adsorption effects of the oxide-based cathodes are often proven to have both physical confinement and chemical adsorption for an effective cathode design. − As a result, the previous success in the development of various oxide-based cathodes and the ambiguous contributions of the physical and chemical polysulfide-trapping capability reported in the literature inspire us to explore the chemical polysulfide adsorption capability of oxide materials.…”

Papaverine Infusion Through Aortic Root before Cardiac Self-recovery in Heart Valve Replacement with TiO2 Nanocrystalline Film Material

“…TiO2 Nanocrystalline film material has been widely used as surface modification material for vascular medical devices (such as artificial vascular stents and artificial heart valves) due to its excellent anticoagulant properties and endothelial cell growth guidance (11)(12)(13). Líšková et al (2020) (14) pointed out that the excellent anticoagulant energy of TiO2 Nanocrystalline film material has exceeded that of pyrolytic carbon material with the highest anticoagulant level.…”

The Strategy of Achieving Flexibility in Materials and Configuration of Flexible Lithium‐Ion Batteries

“…The current developed flexible battery systems mainly include the following types: flexible lithium‐ion batteries, flexible lithium‐sulfur batteries, fuel batteries, solar batteries, etc. Lithium‐sulfur battery [ 8–11 ] is a kind of lithium battery with sulfur as the positive electrode and lithium metal as the negative electrode. As a kind of lithium secondary battery with high capacity, lithium‐sulfur batteries have the advantages of high theoretical capacity and high energy density.…”