Ultra‐Long Helical CNFs 3D‐Networks as High‐Conductivity Current Collectors for Efficient Sodium Deposition

ABSTRACT Aluminum (Al) current collectors are crucial for sodium metal batteries (SMBs), yet sodium (Na) dendrite suppression and uniform Na deposition remain challenges. Surface modification could significantly optimize Na deposition behavior. Herein, a 20 nm copper (Cu) layer is designed to confine NiY diatomic catalyst (DAC) for Al surface modification via magnetron sputtering and heat treatment. The adjacent NiY atoms, with low single‐point energy (–228.05 eV), minimum segregation energy (−0.67 eV), and maximum aggregation energy (5.84 eV), synergistically stabilize diatomic dispersion in the Cu nanolayer. Benefiting from the tailored acetylene adsorption energy (−1.16 eV) and favorable formation energies of C 2 H (−13.58 eV) and C 2 (−11.44 eV), NiY–DAC exhibits excellent catalytic activity, in‐situ growth ultra‐long helical CNFs 3D‐networks with a thickness of 46.3 µm on Al current collectors, enabling efficient Na storage and remarkable inhibition Na dendrite formation. The modified current collector delivers outstanding electrochemical performance. The coulombic efficiency is up to 99.49% over 3000 h of half‐cells at 1.0 mA cm −2 /1.0 mAh cm −2 with a low overpotential (3.1 mV), and the CNFs‐Na||Na 3 V 2 (PO 4 ) 3 full‐cells achieve stable cycling over 1500 cycles at 10.0 C. This diatomic catalyst confinement strategy provides new insight into designing high‐performance carbon‐modified current collectors.