High area capacity and dendrite-free anode constructed by highly potassiophilic Pd/Cu current collector for low-temperature potassium metal battery

Abstract

Potassium metal battery (KMB) have been recognized as a feasible alternative electrochemical energy device for practical application. However, the dendrite growth and the instability of the potassium anode are the major issues hindering its practicability. In this paper, a layer of Pd is coated on the rib surface of Cu foam through a replacement reaction in the liquid-phase synthesis to form Pd/Cu foam current collector, and then K metal is deposited on this Pd/Cu foam to prepare the K/Pd/Cu foam anode material for KMBs. This K/Pd/Cu foam is assembled into a KMB using Prussian blue (PB) as the cathode material to achieve high capacity and cycle-ability even at low-temperature (− 20 °C). Experimental results confirm that this K/Pd/Cu foam can significantly reduce K dendrite growth, increase K+ ion diffusion within the solid electrolyte interface (SEI) film and reduce the side reaction. Based on the experiment measurements, material characterization, and theoretical DFT calculations, the possible enhancement mechanism of the highly potassiophilic interface of Pd/Cu foam during the cycling of KMB is also explored.