Boosting bidirectional sulfur conversion enabled by introducing boron-doped atoms and phosphorus vacancies in Ni2P 2 P for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have gained great attention due to the high theoretical energy density and low cost, yet their further commercialization has been obstructed by the notorious shuttle effect and sluggish redox dynamics. Herein, we supply a strategy to optimize the electron structure of Ni2P 2 P by concurrently introducing B-doped atoms and P vacancies in Ni2P 2 P (Vp-B-Ni2P), p-B-Ni 2 P), thereby enhancing the bidirectional sulfur conversion. The study indicates that the simultaneous introduction of B-doped atoms and P vacancies in Ni2P 2 P causes the redistribution of electron around Ni atoms, bringing about the upward shift of d-band center of Ni atoms and effective d-p p orbital hybridization between Ni atoms and sulfur species, thus strengthening the chemical anchoring for lithium polysulfides (LiPSs) as well as expediting the bidirectional conversion kinetics of sulfur species. Meanwhile, theoretical calculations reveal that the incorporation of B-doped atoms and P vacancies in Ni2P 2 P selectively promotes Li2S 2 S dissolution and nucleation processes. Thus, the Li-S batteries with Vp-B-Ni2P-separators p-B-Ni 2 P-separators present outstanding rate ability of 777 mA h g-1 at 5 C and high areal capacity of 8.03 mA h cm-2 under E/S of 5lL l L mg-1 and sulfur loading of 7.20 mg cm-2 . This work elucidates that introducing heteroatom and vacancy in metal phosphide collaboratively regulates the electron structure to accelerate bidirectional sulfur conversion. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.