Efficient Reversible Conversion between MoS2 and Mo/Na2S Enabled by Graphene‐Supported Single Atom Catalysts

Abstract Sodium‐ion batteries (SIBs) based on conversion‐type metal sulfide (MS) anodes have attracted extraordinary attention due to relatively high capacity and intrinsic safety. The highly reversible conversion of M/Na 2 S to pristine MS in charge plays a vital role with regard to the electrochemical performance. Here, taking conventional MoS 2 as an example, guided by theoretical simulations, a catalyst of iron single atoms on nitrogen‐doped graphene (SAFe@NG) is selected and first used as a substrate to facilitate the reaction kinetics of MoS 2 in the discharging process. In the following charging process, using a combination of spectroscopy and microscopy, it is demonstrated that the SAFe@NG catalyst enables an efficient reversible conversion reaction of Mo/Na 2 S→NaMoS 2 →MoS 2 . Moreover, theoretical simulations reveal that the reversible conversion mechanism shows favorable formation energy barrier and reaction kinetics, in which SAFe@NG with the Fe–N 4 coordination center facilitates the uniform dispersion of Na 2 S/Mo and the decomposition of Na 2 S and NaMoS 2 . Therefore, efficient reversible conversion reaction MoS 2 ↔NaMoS 2 ↔Mo/Na 2 S is enabled by the SAFe@NG catalyst. This work contributes new avenues for designing conversion‐type materials with an efficient reversible mechanism.