Exfoliated 2D Lepidocrocite Titanium Oxide Nanosheets for High Sulfur Content Cathodes with Highly Stable Li–S Battery Performance

Abstract

Despite the high energy densities, lithium–sulfur (Li–S) batteries suffer from insufficient cycle life originating from the shuttling process involving lithium polysulfides (LiPSs). Various approaches have been introduced to resolve the shuttling problem, but they are not usually effective for electrodes with high sulfur contents. Here, we report an exfoliated 2D lepidocrocite titanium oxide nanosheet as a component for sulfur cathodes to suppress polysulfide dissolution markedly. In particular, the Lewis acidity originating from undercoordinated Ti species as well as the large surface area associated with the 2D structure endow 2D lepidocrocite titanium oxide with an efficient interaction with LiPSs. As a result, even with a sulfur content of 80 wt %, the Li–S cell exhibits 1023.5 mAh g–1 at 50 mA g–1 and a capacity retention of 82.3% after 300 cycles measured at 1000 mA g–1. The considerably improved cycling performance provides useful insight for designing sulfur cathodes, that is, the incorporation of acidic 2D metal oxide nanosheets.

Integration of Binary Active Sites: Co3V2O8 as Polysulfide Traps and Catalysts for Lithium‐Sulfur Battery with Superior Cycling Stability

“…[ 25–30 ] Therefore, a series of active materials (such as metal oxides/sulfides) with chemically polar sites were also fabricated to anchor the LiPS via the formation of the chemical bonding. [ 31–37 ] In addition to the effective immobilization of the LiPS, the rapid conversion of the intermediates on the surface of active materials with catalytic activity is also conducive to enhance the performance of Li‐S batteries. [ 38–46 ] However, the synergetic effect of chemical interaction and catalytic activity are not attracting much attention.…”

Processes associated with ionic current rectification at a 2D-titanate nanosheet deposit on a microhole poly(ethylene terephthalate) substrate

“…Applications of titanate nanosheets have been proposed as component in batteries [22], in heterogeneous catalysis [23], in photocatalysis [24] and as functional filler in polymer blends [25]. Recently, we have demonstrated that a film deposit of titanate nanosheet material on a glassy carbon electrode allows ferroceneboronic acid to be immobilised and binding of fructose within the nano-lamellar space to be detected [20].…”

Titelbild: Oxygen Vacancies on Layered Niobic Acid That Weaken the Catalytic Conversion of Polysulfides in Lithium–Sulfur Batteries (Angew. Chem. 33/2019)

“…Theu ltrathin structures are considered as excellent models to study the adsorption behavior of LiPSs. [7] They possess alarge electroactive surface with sufficient active sites for promoting the catalytic reactions. [8] Therefore,i ti s promising to use ultrathin structure to study the difference between the pristine surface and oxygen-vacancy-defects rich surfaces,w hich is more evident for us to gain an insightful understanding of the surface defect in catalytic reactions.I n this work, we have carried out aL ewis solid acid HNO ultrathin nanobelt for Li-S battery.…”