Potassiophilic α-MoC anchored on 3D carbon host enables uniform potassium nucleation and super-stable potassium metal anodes

Abstract

Potassium metal anodes are desirable for the advantages of low price, high abundance, and similar standard redox potential with metallic lithium. However, dendritic growth and large volume changes impede its practical application. Herein, a dendrite-free and stable potassium metal composite anode has realized by infusing metallic potassium into an α-MoC modified carbon cloth (α-MoC@CC). The prepared α-MoC@CC as a 3D host exhibits an intrinsic potassiophilicity based on experimental investigations and density functional theory (DFT) calculations, which not only facilitates fast molten potassium wetting but also reduces nucleation overpotential. In addition, the current density distribution of the composite anode carried out by COMSOL Multiphysics reveals that the 3D host can effectively reduce current density and inhibit dendrite growth. Consequently, the K@α-MoC@CC composite anode displays stable plating/stripping profiles for more than 2000 h with low polarization in symmetric batteries. As a practical device application, the K@α-MoC@CC composite anode demonstrates superior suitability when paired with Prussian blue cathode in a full battery. Significantly, this work represents an effective pathway to regulate potassium metal anode towards practical applications.