3D bead-like Cu2S/NC nanofiber fabric as an interlayer for fabricating dendrite-free lithium metal anodes

Abstract

Uncontrollable lithium dendrite growth and huge volume changes hinder the practical applications of lithium metal anodes. Herein, a 3D bead-like nitrogen-doped carbon nanofiber fabric modified with Cu₂S nanocubes (Cu₂S/NCs) was successfully designed as an interlayer between the separator and lithium metal anode. The 3D porous conductive structure could relieve the volume change in the electrode and reduce local current density. Cu₂S implanted into the framework as lithophilic sites induced uniform Li nucleation/deposition and inhibited lithium dendrite growth. The Cu₂S/NC interlayer could achieve a stable solid–electrolyte interphase (SEI) layer for protecting the lithium metal anode. As a result, a higher coulombic efficiency exceeding 99% after 250 cycles at a current density of 1.0 mA cm⁻² and a capacity of 1.0 mA h cm⁻² as well as a prolonged lifespan of over 2500 h for a Li||Li symmetric cell with the Cu₂S/NC interlayer could be realized. The full cell coupled with LiFePO₄ exhibited an outstanding rate capability up to 5.0 C and long-term electrochemical cycling stability for over 1200 cycles.