Densified Metallic MoS2/Graphene Enabling Fast Potassium‐Ion Storage with Superior Gravimetric and Volumetric Capacities

Abstract

AbstractThe potassium‐ion battery (PIB) is an attractive energy storage device that possesses the potential advantages of high energy density and low cost. Herein, a pure 1T‐MoS2 is synthesized on graphene oxide and assembled into a hydrogel. The hydrogel is further tightened to a compact 1T‐MoS2/graphene (CTMG) bulk by a densifying strategy of capillary tension. When employed as an anode for PIBs, the CTMG electrode can store K+ through reversible intercalation and conversion electrochemistry, accompanied with fast kinetics since the 1T‐MoS2 induces a pseudocapacitive storage mechanism and the extraordinary K+ transportation ability. Consequently, the CTMG electrode delivers the high and reversible rate capacities of 511 and 327 mAh g‐1 at 0.1 and 1 A g‐1, respectively. Moreover, the compact architecture reduces the electrode thickness by ≈33% enabling a high volumetric capacity (512 mAh cm‐3 at 0.1 A g‐1 after 100 cycles), as well as holding a promising application in thick electrode.