A stable and ultrafast K ion storage anode based on phase-engineered MoSe2.

Potassium-ion batteries (PIBs) are attracting increasing attention due to the abundance of K resources, but the sluggish kinetics and inferior cycling stability of anodes still hinder their application. Herein, we present a hybrid 1T/2H phase MoSe2 anode, which shows noticeable pseudocapacitive response and fast kinetics for K storage. Correspondingly, superior electrochemical performances including a high reversible capacity of 440 mA h g-1 after 100 cycles at 0.1 A g-1 and superb rate capacity of 211 mA h g-1 at 20.0 A g-1 are achieved. We believe this work may shed light on the phase engineering of transition metal compounds for rapid charging PIBs.