Boosting potassium storage performance via construction of NbSe2–based misfit layered chalcogenides

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have become promising anode materials for potassium-ion batteries (KIBs) due to their high theoretical capacity and large interlayer spacing. The application of TMDCs is prevented by their volume expansion during cycling and relatively poor conductivity. Herein, we developed a general strategy to prepare a series of NbSe2-based misfit layered compounds MLCs ((SnSe)1.16NbSe2, (PbSe)1.14NbSe2) by a facile top-down process. The unique sandwich structure of MLCs combines the excellent structure stability and conductivity of NbSe2 with the high reactivity of selenides (SnSe and PbSe), which greatly improves the potassium storage performance. The high-strength lamella and weak interlayer bonding of NbSe2 improve the K+ diffusion rate, leading to high rate-capability of the MLCs. This work provides a new avenue for designing novel types of sandwich structured electrode materials for energy storage systems.