Reshaping two-dimensional MoS₂ for superior magnesium-ion battery anodes

Few-atom-thick two-dimensional (2D) molybdenum disulfide (MoS₂) monolayers possess numerous crucial applications in energy storage. Usually, the strategy of activating interfacial electron transfer was employed to promote their performance. Herein, we reshape the structure of materials to excite their subinterfacial and interfacial electron transfer for superior metal-ion batteries. As an example, we rationally design and reconfigure the structure of 2D MoS₂ and propose a new stable structure, B-MoS₂, which has an S-Mo-S sandwich structure with a buckled square lattice. The B-MoS₂ monolayer is a promising anode material for magnesium-ion batteries (MgIBs) with a high capacity (921.3 mA h g^-1) and a low averaged open circuit voltage (0.154 V). Multiscale underlying mechanisms for the storage of Mg and Li ions in MoS₂ are provided. Based on the electronic level, the high capacity is ascribed to the occurrence of interfacial and subinterfacial electron transfer between metal ions and B-MoS₂. Based on the atomic level, the insertion-adsorption mechanism or adsorption-insertion mechanism is determined for different ion storage at B-MoS₂. The intrinsic metallic property of B-MoS₂ and the enhanced electronic conductivity of Mg/B-MoS₂ systems as well as low migration barriers (∼0.604 eV) of Mg ions at MoS₂ suggest that the B-MoS₂ anode has fast charge/discharge rates. This work offers novel concepts (i.e. subinterfacial electron transfer and its activation) for superior energy storage materials, and proposes new multiscale underlying mechanisms for ion storage in the MoS₂ family.