Vacancy‐Defect Topological Insulators Bi₂Te_3−x Embedded in N and B Co‐Doped 1D Carbon Nanorods Using Ionic Liquid Dopants for Kinetics‐Enhanced Li–S Batteries

Abstract

Lithium–sulfur (Li–S) batteries are hindered by the shuttle effect and the sluggish redox kinetics of polysulfides. In this study, topological insulators (TIs) Bi2Te3−x with abundant Te vacancies embedded in N and B co‐doped carbon nanorods (Bi2Te3−x@NBCNs) are synthesized and used as sulfur host composites for high‐performance Li–S batteries. Bi2Te3−x@NBCNs effectively enhance the intrinsic conductivity, strengthened the chemical affinity, and accelerated the redox kinetics of polysulfides. 1D carbon nanorods with N and B co‐doped heteroatoms endowed with abundant polar sites improve the chemical affinity of polysulfides, while the embedded Bi2Te3−x nanoparticles further promote the nucleation and electrodeposition of Li2S2/Li2S. In situ Raman spectroscopy confirms that Bi2Te3−x@NBCNs effectively reduced cathode‐side accumulation of polysulfides and suppressed the shuttle effect. Owing to the extraordinary synergistic effects of rich heteroatom polar sites and conductive topological surface states, Bi2Te3−x@NBCN‐based cells exhibit a high initial specific capacity of 1264 mAh g−1 at 0.2 C and ultra‐long lifetime (>1000 cycles, with a degradation rate of 0.02% per cycle at 1.0 C). The fundamental insights offered by this work are likely to enable improvement of the electrochemical performance of Li–S batteries based on TI materials.

Topological insulator bismuth selenide with a unique cloud-like hollow structure as a bidirectional electrocatalyst for robust lithium–sulfur batteries

“…Based on this, D Li + can be evaluated with the Randles- Sevcik equation. 39 As shown in Fig. 5d-f, there are good linear correlations between the square root of scan rates and the peak currents in the Bi 2 Se 3 /PP battery.…”

“…38 Most recently, Hu et al synthesized TI Bi 2 Te 3− x nanoparticles embedded in N/B co-doped carbon nanorods as a sulfur host, which demonstrated strong chemisorption and superior catalytic activity with respect to LiPSs. 39 Nevertheless, the applications of TIs in electrochemical energy storage are still at an early state and construction of TIs with desired morphology and structure still remains a hard task. It is worth mentioning that the topological surface states of TIs are active and robust in catalytic reactions, which may be conducive to averting the passivation of electrocatalysts.…”

High Energy Density Aqueous Zinc–Chalcogen (S, Se, Te) Batteries: Recent Progress, Challenges, and Perspective

“…Benefiting from the physical confinement of the carbon substrate, the intrinsic shortcoming of S-based composites can be apparently enhanced. [96][97][98] Impressively, these micro-/nanostructured carbon materials will not only facilitate electrolyte penetration into electrode to boost zinc-ion diffusion kinetics, but also buffer the volume fluctuation of S cathode during the dynamic cycling. [99][100][101] A pioneering work was carried out by using carbon-nanotube-supported 50 wt% sulfur (generalized as S@CNT-50) as a conversional cathode, Jiang and co-workers designed a rechargeable and cost-effective aqueous Zn-S battery, as indicated in Figure 3a.…”

Combined Defect and Heterojunction Engineering in ZnTe/CoTe2@NC Sulfur Hosts Toward Robust Lithium–Sulfur Batteries

“…[ 19b ] Numerous other previous works have explored the effects of oxygen and sulfur vacancies on the performance of LSBs, however, the chemical affinity and catalytic activity of Te vacancies as LiPSs have been very rarely considered. [ 11b,20 ]…”