Nanosheets assembled layered MoS2/MXene as high performance anode materials for potassium ion batteries

Potassium ion batteries (KIBs) have attracted intensive attention considering its similar chemistry with lithium and sodium, nature abundance and low cost of potassium source. However, huge volume expansion and sluggish kinetics induced by large radius of K+ usually lead to low capacity and poor cycling life for most electrodes. Herein, nanosheets assembled layered Ti3C2Tx MXene/MoS2 composites are rationally designed and prepared as new anodes for KIBs. The MoS2 nanosheets anchor on the conductive MXene substrate vertically to form a hierarchical 2D structure, which not only facilitates fast ion and electrons transport, but also effectively accommodates the large volume expansion of MoS2 nanosheets, and prevents restacking of MXene sheets. The effect of different amount of MXene on morphology and potassium storage properties is investigated. Benefits of the unique structural charactertics of layered structure, high conductivity and excellent pseudocapacitive property, the hybrids exhibit enhanced reversible capacity of 290.7 mAh g−1 at 50 mA g−1, high rate capacity and long cycling stability for potassium ion batteries. This work sheds light on designing high performance electrode materials with layered MXene and two dimensional transition metal chalcogenide, open a new pathway of developing advanced materials for K ion energy storage devices.