Two-dimensional transition metal dichalcogenides (2D TMDs) are fundamentally fascinating and chemically versatile materials for a variety of applications. Among various TMDs, molybdenum disulfide (MoS2) has been intensively investigated due to its extraordinary intrinsic properties such as high optical absorption, active catalytic sites, high Young's modulus and Seebeck coefficient. These properties have made MoS2 highly desirable in many research domains including heterojunction solar cells, electro/photocatalysis, strain sensors and thermoelectric devices. Particularly, the layered structure composed of S-Mo-S slabs provides highly accessible sites, resulting in MoS2 being a promising electrode material for battery applications. In the area of potassium-ion batteries (PIBs) where the large size of K-ion poses a major challenge for electrode materials discovery, the wide interlayer spacing (0.62 nm) and weak Van der Waals interaction between the S-Mo-S slabs can effectively accommodate K-ions and lower the energy barrier of K-ion diffusion. The capability to transfer up to four electrons per MoS2 formula indicates a high theoretical capacity (670 mAh g -1 ).