Engineering the Catalytic Superlattices for Highly Reversible Sodium‐Ion Storage with A high Compositional Conversion Degree

A major obstacle of transition metal disulfides in sodium‐ion batteries is compositional irreversible conversion, leading to fast capacity decay. Here, we propose to engineer a catalytic superlattice structure for achieving a record‐high compositional reversible conversion degree (≈100%). The superlattice is constructed by alternately stacking MoS2 layers and nitrogen/oxygen co‐doped reduced graphene oxide‐supported single‐atom metal layers (MoS2/M‐ONG SL, M=Fe, Co, Ni, Cu, Zn) with 100% MoS2/M‐ONG interfaces, in which the metal atoms bridge the two layers through S‐M‐O chemical bonds. Using MoS2/Co‐ONG SL as a model, the unique superlattice structure shows excellent electron and Na+ transport properties during discharge and charge. Moreover, the Co‐ONG boosts Na2S adsorption and decomposition by forming Co‐3d and S‐3p hybridization. As a result, the MoS2/Co‐ONG SL shows a high compositional reversible conversion degree(≈100%), as proven by a series of in‐/ex‐situ spectroscopic analyses. As a result, the MoS2/Co‐ONG SL exhibits a stable cycling stability of 300.7 mAh g‐1 after 2000 cycles at 2 A g‐1, with an ultrasmall capacity decay rate of 0.41% per 100 cycles. This work offers a noteworthy perspective on the design and fabrication of conversion‐type materials, emphasizing the crucial role of interface engineering in achieving excellent bidirectional reaction kinetics.