Regulating Interfacial Ion and Electron Transport for Dendrite-Free Potassium Metal Anodes

Potassium metal batteries (PMBs) face challenges of interfacial instability and dendritic growth. Herein, an integrated potassium metal anode (K-Cu@OC) is fabricated by cold-rolling metallic K with an intermediate medium composed of Cu nanoparticle-embedded oxygen-doped carbon composite, enabling simultaneous regulation of ion transport and electron localization at the interface. Experimental and theoretical analyses indicate that oxygen species functional groups boost K⁺ transport kinetics and guide uniform nucleation. Meanwhile, the Cu/OC heterointerface promotes directional electron transfer and spatially regulated K⁺ uniform deposition by establishing localized electron-rich regions. Consequently, the anode interface remains dendrite-free and exhibits enhanced electrochemical stability. The symmetric cell exhibits exceptional cycling stability exceeding 2800 h at 0.5 mA cm^-2 and 1480 h at 1.0 mA cm^-2. Furthermore, the full cell maintains a reversible capacity of 93.4 mAh g^-2 over 600 cycles with minimal voltage hysteresis. This work highlights the critical role of interfacial chemical and electronic engineering in stabilizing K metal anodes, providing a scalable and practical strategy for achieving high-performance PMBs.