Lithium/Sodium Deposition Behavior and Dendrite Inhibition Mechanism on Metal-Modified and Nitrogen-Doped Carbon Nanotube Skeletons

Nitrogen-doped and metal-modified carbon-based skeletons have been commonly used to improve the Li/Na deposition behavior and dendrite inhibition for alkali metal batteries. However, the synergistic mechanism between nitrogen-doped and metal-modified strategies has not been systematically studied. Herein, to understand the plating/stripping of alkali metals on/from metal-modified and nitrogen-doped carbon nanotube (CNT) skeletons, the lithium binding energy, charge transfer, and state density between lithium and various carbon skeletons were calculated to demonstrate the fluctuation law of lithium/sodium affinity at the modified sites. The results illustrate that the N-doped CNT skeletons modified with Co or Fe clusters (Co-NCNTs or Fe-NCNTs) have high infiltration ability and affinity toward alkali metals, which could be employed as uniform nucleation sites to direct Li/Na deposition. In light of this, two carbon/lithium composite anodes were created by carbon fibers linked to three-dimensional skeletons (CC@Co-NCNTs and CC@Fe-NCNTs) which were filled with molten lithium. The measurement of the Li deposition overpotential served as an additional evidence of the skeletons' affinity for lithium. This work demonstrates the direction for the investigation of the dendrite inhibition mechanism and lithiophilicity/sodiophilicity enhancement of CNT carbon skeletons.