Semi-Solid CNT@NaK Anode for Potassium Metal Battery

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 approximate to 90%. This discovery provides a new idea for establishing dendrite-free anodes for K metal batteries.