Synergistic Stabilization of Potassium Metal Anodes Through Orange-Peel Elimination and Robust Solid-Electrolyte...

Potassium (K) metal anodes are attractive for next-generation rechargeable batteries due to their low redox potential and elemental abundance, yet their practical application is hindered by dendrite growth and unstable solid-electrolyte interphases (SEIs). Here, we replace conventional roll pressing with a cutting-based fabrication strategy to produce crystallographically more uniform and minimally deformed K surfaces, while independently tuning SEI chemistry through electrolyte concentration. This approach establishes a unified framework that elucidates the synergistic coupling between surface uniformity and SEI robustness in governing K plating/stripping stability. Only their synergy delivers fast kinetics, high areal capacity, and long-term reversibility. Consequently, optimized K||K symmetric cells operate stably for over 4 000 h at 0.5 mA cm^-2 and 4 mA h cm^-2. Full cells paired with K_1.97Mn[Fe(CN)₆] cathodes retain 90% capacity after 1200 cycles. These findings highlight the importance of concurrent morphological and interfacial regulation for practical K metal anodes.