Publication
NbSe2 Meets C2N: A 2D‐2D Heterostructure Catalysts as Multifunctional Polysulfide Mediator in Ultra‐Long‐Life Lithium–Sulfur Batteries
Publisher:
Wiley
Date:
12-08-2021
DOI:
10.1002/AENM.202101250
Abstract: The shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPS) h er the practical application of lithium–sulfur batteries (LSBs). Toward overcoming these limitations, herein an in situ grown C 2 N@NbSe 2 heterostructure is presented with remarkable specific surface area, as a Li–S catalyst and LiPS absorber. Density functional theory (DFT) calculations and experimental results comprehensively demonstrate that C 2 N@NbSe 2 is characterized by a suitable electronic structure and charge rearrangement that strongly accelerates the LiPS electrocatalytic conversion. In addition, heterostructured C 2 N@NbSe 2 strongly interacts with LiPS species, confining them at the cathode. As a result, LSBs cathodes based on C 2 N@NbSe 2 /S exhibit a high initial capacity of 1545 mAh g −1 at 0.1 C. Even more excitingly, C 2 N@NbSe 2 /S cathodes are characterized by impressive cycling stability with only 0.012% capacity decay per cycle after 2000 cycles at 3 C. Even at a sulfur loading of 5.6 mg cm −2 , a high areal capacity of 5.65 mAh cm −2 is delivered. These results demonstrate that C 2 N@NbSe 2 heterostructures can act as multifunctional polysulfide mediators to chemically adsorb LiPS, accelerate Li‐ion diffusion, chemically catalyze LiPS conversion, and lower the energy barrier for Li 2 S precipitation/decomposition, realizing the “adsorption‐diffusion‐conversion” of polysulfides.