Formation of hollow nanofiber rolls through controllable carbon diffusion for Li metal host

Lithium metal has long been seen as a promising battery anode due to its high specific capacity and low anode potential. However, serious safety hazards and poor electrochemical performance caused by uncontrollable dendritic growth hinder its practical application. Here, a stable lithium@nanofiber roll composite electrode is developed by utilizing the carbon diffusion effect. By combining carbon with different metallic elements, a hollow structure with inner lithiophilic surface has been successfully obtained through an orderly chemical potential gradient. The as-prepared nanofiber rolls are demonstrated as the host to accommodate lithium metal and impressively, superior electrochemical performance can be achieved by the resulting composite electrode with high coulombic efficiency of ∼99.6% for over 1400 cycles at 0.5 mA cm⁻², 1 mA h cm⁻². This study presents new insights in understanding the carbon diffusion and may open up new avenues for preparing fiber-based Li-metal host.