Interlayer engineering of MoS2 nanosheets for high-rate potassium-ion storage

As a conventional two-dimensional material, MoS2 has small interlayer spacing and poor electrochemical performance. Therefore, Se–MoS2 is synthesized by doping Se into MoS2 through a simple alloying process to expand the interlayer spacing and have more active sites. Using Se–MoS2 for potassium ion batteries can alleviate the structural changes of the alloy in potassium ion storage and have high rate performance. When the current density increases from 50 to 2000 mA g−1 and then returns to 50 mA g−1, the reversible capacity of Se–MoS2-2 remains at 75%. The introduction of anions not only leads to the expansion of the interlayer spacing of MoS2 but also exposes more active sites, making it easier to insert and extract potassium ions during storage, and providing more options for designing excellent electrode materials for potassium ion batteries.