Orbital-Tailoring Strategy via Dual-Defect Engineering in P-FeTe<sub>2-x</sub>@NC Synergizes Polysulfide Adsorption-Conversion for Lithium-Sulfur Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 40913507.
- Also identified by DOI 10.1002/adma.202511910.
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Abstract
The polysulfide shuttling and sluggish sulfur redox kinetics hinder the commercialization of lithium-sulfur (Li-S) batteries. Herein, the fabrication of phosphorus (P)-doped iron telluride (FeTe<sub>2</sub>) nanoparticles with engineered Te vacancies anchored on nitrogen (N)-doped carbon (C) (P-FeTe<sub>2-x</sub>@NC) is presented as a multifunctional sulfur host. Theoretical and experimental analyses show that Te vacancies create electron-deficient Fe sites, which chemically anchor polysulfides through enhanced Fe─S covalent interactions. Additionally, P doping shifts the Fe d-band center toward the Fermi level, increasing the affinity for polysulfide intermediates through d-p orbital hybridization. This dual modulation strengthens the built-in electric field at the P-FeTe<sub>2-x</sub>/NC interface, effectively suppressing the shuttle effect and accelerating redox kinetics. The optimized P-FeTe<sub>2-x</sub>@NC host enables Li-S batteries to achieve an initial capacity of 1475.6 mAh g<sup>-1</sup> at 0.1 C and remarkable cycling stability, exhibiting only a 0.031% capacity decay per cycle over 1000 cycles at 1 C. High sulfur utilization is evidenced by attaining 6.51 mAh cm<sup>-2</sup> areal capacity under a loading of 7.80 mg cm<sup>-2</sup>, while a 2.67 Ah pouch cell delivers an energy density of 326.6 Wh kg<sup>-1</sup>. This work establishes a vacancy-doping synergy strategy for coordinating adsorption and conversion processes in sulfur electrochemistry, offering new insights into the design of high-energy-density batteries.