Selective Potassium Deposition Enables Dendrite‐Resistant Anodes for Ultrastable Potassium‐Metal Batteries

Abstract

AbstractInstability at the solid electrolyte interface (SEI) and uncontrollable growth of potassium dendrites have been pressing issues for potassium‐ion batteries. Herein, a self‐supporting electrode composed of bismuth and nitrogen‐doped reduced graphene oxide (Bi80/NrGO) is designed as an anode host for potassium‐metal batteries. Following the molten potassium diffusion into Bi80/NrGO, the resulting K@Bi80/NrGO exhibits unique hollow pores that provide K+‐diffusion channels and deposition space to buffer volume expansion, thus maintaining the electrode structure and SEI stability. The K@Bi80/NrGO also provides a controlled electric field that promotes uniform K+ flux, abundant potassiophilic N sites, and Bi alloying active sites, collectively enabling precise nucleation and selective deposition of potassium to achieve dendrite‐resistant anodes. With the K@Bi80/NrGO‐based optimized electrodes, the assembled K@Bi80/NrGO symmetrical cells can sustain stable cycling over 3000 h at a current density of 0.2 mA cm−2. Full cells with a Prussian blue cathode and K@Bi80/NrGO anode exhibit high stability (with no degradation for 1960 cycles at 1000 mA g−1) with 99% Coulombic efficiency. This work may lead to the design of anodes with the triple attributes of precise nucleation, smooth diffusion, and dendrite inhibition, ideal for developing stable potassium‐metal anodes and beyond.