P-Doped NiTe₂ with Te-Vacancies in Lithium–Sulfur Batteries Prevents Shuttling and Promotes Polysulfide Conversion

Lithium–sulfur (Li–S) batteries have been hindered by the shuttle effect and sluggish polysulfide conversion kinetics. Here, a P-doped nickel tellurium electrocatalyst with Te-vacancies (P⊂NiTe_2−x) anchored on maize-straw carbon (MSC) nanosheets, served as a functional layer (MSC/P⊂NiTe_2−x) on the separator of high-performance Li–S batteries. The P⊂NiTe_2−x electrocatalyst enhanced the intrinsic conductivity, strengthened the chemical affinity for polysulfides, and accelerated sulfur redox conversion. The MSC nanosheets enabled NiTe₂ nanoparticle dispersion and Li⁺ diffusion. In situ Raman and ex situ X-ray absorption spectra confirmed that the MSC/P⊂NiTe_2−x restrained the shuttle effect and accelerated the redox conversion. The MSC/P⊂NiTe_2−x-based cell has a cyclability of 637 mAh g^-1 at 4 C over 1800 cycles with a degradation rate of 0.0139% per cycle, high rate performance of 726 mAh g^-1 at 6 C, and a high areal capacity of 8.47 mAh cm^-2 under a sulfur configuration of 10.2 mg cm^-2, and a low electrolyte/sulfur usage ratio of 3.9. This work demonstrates that vacancy-induced doping of heterogeneous atoms enables durable sulfur electrochemistry and can impact future electrocatalytic designs related to various energy-storage applications.