Ultrathin K–C Composite Anode Enables Conformal Stripping/Plating for Dendrite-Free and High-Rate Potassium-Metal Batteries

The development of metallic K is seriously hampered by low melting point, high reactivity, and uncontrollable dendrite growth. Herein, benefiting from the super-potassiophility of CNTs (carbon nanotubes), K@CNT composite anodes are prepared via a rational fused-modeling approach, where CNTs build interconnected frameworks and K atoms are anchored on CNTs, inducing depressed atomic creeping and flowability at high temperatures. Thereby, K@CNT composite anodes deliver flexibility, processability (∼30 μm), and thermal stability (up to 300 °C). In particular, K@CNT composite anodes exhibit a conformal stripping and plating behavior along with the plane-structure of the CNT framework during charge–discharge processes under 10 mA cm–2 without dendrites. Moreover, the K@CNT // Prussian white full cells exhibit high rate performance (60.9 mAh g–1 at 3000 mA g–1), high energy density (187.3 Wh kg–1), and high-temperature stability. This work provides an avenue for designing high-performance metallic K anodes and for driving the commercialization of K-metal batteries.