Helical nitrogen-doped carbonaceous nanotubes with periodic surface curvature as robust anodes for lithium and sodium storage.

Surface curvature can modulate the electronic structure and alkali-ion adsorption behavior of carbon materials, yet the energy-storage function of interfaces with continuous periodic curvature remains poorly understood. Herein, helical N-doped carbon nanotubes (H-NCNTs) with periodically curved surfaces were synthesized via chiral-template-directed polymerization of pyrrole followed by carbonization. Electrochemical kinetic analyses revealed that both Li- and Na-ion storage processes in H-NCNT-600 are dominated by rapid surface pseudocapacitive reactions, highlighting the important contribution of interfacial ion adsorption to its storage capacity and reaction kinetics. Density functional theory (DFT) calculations showed that helical curvature strengthens ion‑carbon surface interactions, while nitrogen sites further stabilize ion adsorption. This study demonstrates the cooperative enhancement effect of helical curvature and nitrogen sites on Li+/Na+ adsorption, providing new insights into the topological design of carbon-based anodes for high-performance lithium/sodium-ion batteries.