Anode-Free Lithium Metal Battery Enabled by Oxygen-Functionalized MWCNT and TiN Interlayer for Uniform Lithium Deposition

Anode-free lithium metal batteries (AFLMBs), with high energy density, low cost, and enhanced safety, are regarded as the next-generation high-energy-density batteries. However, capacity decay and uncontrollable dendritic Li growth hinder its practical adoption. Hence, a Cu@TiN-MWCNT interfacial layer was rationally designed on Cu foil to enable highly reversible Li deposition/stripping. TiN nanoparticles provide abundant lithiophilic sites to reduce the Li nucleation overpotential, while COOH-functionalized multi-walled carbon nanotubes construct a conductive network to decrease local current density and improve interfacial stability. Moreover, oxygen-containing carboxyl groups promote lithium salt dissociation and facilitate the formation of a LiF-rich solid electrolyte interphase, further stabilizing the electrode/electrolyte interface and suppressing dendritic Li growth. Benefiting from these synergistic effects, compact and uniform Li deposition is achieved. As a result, the Li/Cu@TiN-MWCNT||LFP cell with a low N/P ratio of 2.1 maintains a specific capacity of 144.15 mAh g −1 after 150 cycles at 3 C. Additionally, the AFLMB exhibits a high-capacity retention of 51.41% and coulombic efficiency of 98.67% after 80 cycles, which points out a new direction for the development of current collectors toward high-performance AFLMBs.