Evolution of Stabilized 1T-MoS 2 by Atomic-Interface Engineering of 2H-MoS 2 /Fe-N x towards Enhanced Sodium Ion Storage.

Metallic conductive 1T phase molybdenum sulfide (MoS 2 ) has been identified as promising anode for sodium ion (Na + ) batteries, but its metastable feature makes it difficult to obtain and its restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic-interface engineering is employed for constructing 2H-MoS 2 layers assembled on single atomically dispersed Fe-N-C (SA Fe-N-C) anode material that boosts its reversible capacity. The work-function-driven-electron transfer occurs from SA Fe-N-C to 2H-MoS 2 via the Fe-S bonds, which enhances the adsorption of Na + by 2H-MoS 2 , and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS 2 with the ferromagnetic spin-polarization of SA Fe-N-C occurs during the sodiation/desodiation process, which significantly enhances the Na + storage kinetics, and thus the 1T/2H MoS 2 /SA Fe-N-C display a high electronic conductivity and a fast Na + diffusion rate.