Semi‐Solid CNT@NaK Anode for Potassium Metal Battery

Abstract The CK bond plays a significant role in stabilizing the Na‐K (NaK) alloy electrodes due to the enhancive interfacial affinity. In this study, a method for constructing semi‐solid K metal electrodes with rich CK bonds by in situ replacement of N‐doped carbon nanotubes (CNT) and liquid NaK alloy is proposed. Based on the in situ infrared thermal imaging technique combined with heat calculation, X‐ray photoelectron spectroscopy elemental analysis, and reaction thermodynamic calculation, graphite‐N, which is widely distributed on the wall of CNT, offers plenty of replacement sites for forming CK bonds. Due to the rich bonds, the amount of CNT sharply reduces in dendrite‐free semi‐solid CNT@NaK electrodes and the activity of NaK alloy raises to ≈90%. This discovery provides a new idea for establishing dendrite‐free anodes for K metal batteries.