Display omitted A dendrite-free and ultra-stable potassium metal composite anode has realized by infusing metallic potassium into a 3D potassiophilic α-MoC modified carbon cloth. Both the density functional theory (DFT) calculations and COMSOL Multiphysics demonstrate that the potassiophilic 3D host not only can facilitate fast molten potassium wetting and reduce nucleation overpotential but also homogenize the distribution of current density and inhibit potassium dendrite growth. •Dendrite-free K metal anode has realized by potassiophilic α-MoC modified host.•3D potassiophilic host reduces nucleation overpotential and inhibits dendrite.•3D potassiophilic host homogenizes the distribution of current density.•DFT and COMSOL demonstrate the effectiveness of 3D potassiophilic host. 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.