In Situ Formation of a Li 3 N/LiAl Hybrid Network in a Carbon Host for Stable Lithium Metal Anodes

Lithium metal is regarded as the ultimate anode for next‐generation high‐energy‐density batteries owing to its ultrahigh theoretical capacity and lowest electrochemical potential. However, its practical application is severely hindered by low Coulombic efficiency, large volume fluctuations, and safety hazards arising from uncontrollable dendrite growth. Herein, we design a three‐dimensional composite Li metal anode via a scalable route: carbon nanotubes with acetylene black to form spherical hosts, followed by molten Li infusion in the presence of aluminum nitride (AlN) particles. Benefiting from the in situ reaction between Li and AlN, a hybrid network of highly Li + ‐conductive Li 3 N and lithiophilic LiAl alloy is uniformly generated within the carbon framework, creating a mixed electron/ion conduction pathway. This 3D architecture provides enhanced interfacial area, homogenizes Li + flux, buffers volume expansion, and effectively suppresses dendritic Li deposition. Consequently, symmetric cells achieve ultrastable cycling for over 2400 h at 1 mA cm −2 . When paired with a LiFePO 4 cathode, full cells deliver 158 mAh g −1 and retain 82.2% capacity after 500 cycles at 1 C. Moreover, with a sulfur cathode, the full cell achieves a high capacity of 1167 mAh g −1 with 86% retention after 100 cycles at 0.2 C and 70.8% retention after 450 cycles at 1 C.