N, S‐Codoped 3D Carbon Protected Nanoporous MnS With Record High Sodium Ion Storage Performance for Potential Industry Applications

With a high theoretical capacity, the MnS anode, however, exhibits a rather complex sodium diffusion kinetics and poor mechanical stability that hinder its application in sodium‐ion batteries (SIBs). In this work, a simple, economical, and scalable strategy is developed to inherently coat nanoporous MnS with a 3D N, S co‐doped thin carbon layer by using commercially available MnCO3 as precursors. Specifically, the strategy involves a two‐step annealing process, which converts the MnCO3 microparticles into nanoporous Mn2O3 and MnS step by step. The 3D N, S codoped carbon layer is in situ formed during the second annealing process by first coating the nanoporous Mn2O3 with a polyaniline layer. Due to the inherent 3D carbon protection and the strong electronic interaction between N, S dopants and MnS, the N, S codoped carbon protected MnS obtained at 900 °C (NS‐C@MnS‐900) anode displays a high specific capacity of 845 mAh g−1 at 0.1 A g−1, which is higher than all reported MnS‐based SIB anodes. It also shows an outstanding cyclability and rate performance, maintaining a stable capacity of ≈493 mAh g−1 after 1300 cycles at 10 A g−1, which is also the best according to knowledge. These exceptional electrochemical performances and the scalable/simple/low‐cost synthesis make the NS‐C@MnS‐900 attractive for industry application. Nanoporous MnS with inherent 3D N, S codoped carbon protection layer and potential N–Mn, S–Mn interactions exhibit a record high performance for sodium ion battery anode.