P-Doped NiTe 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 ) anchored on maize-straw carbon (MSC) nanosheets, served as a functional layer (MSC/P⊂NiTe ) on the separator of high-performance Li-S batteries. The P⊂NiTe electrocatalyst enhanced the intrinsic conductivity, strengthened the chemical affinity for polysulfides, and accelerated sulfur redox conversion. The MSC nanosheets enabled NiTe nanoparticle dispersion and Li diffusion. In situ Raman and ex situ X-ray absorption spectra confirmed that the MSC/P⊂NiTe restrained the shuttle effect and accelerated the redox conversion. The MSC/P⊂NiTe -based cell has a cyclability of 637 mAh g at 4 C over 1800 cycles with a degradation rate of 0.0139% per cycle, high rate performance of 726 mAh g at 6 C, and a high areal capacity of 8.47 mAh cm under a sulfur configuration of 10.2 mg cm , 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.