Ultrathin electrochemical layer tailoring of lithiophilic materials with 3D hierarchical configuration for lithium metal batteries: Sn/Cu6Sn5@Cu2+1O nanowires on Cu foam

Abstract

Lithium (Li) metal has outstanding electrochemical properties and is a promising anode material for next-generation Li batteries, owing to its large specific capacity and low reduction potential. However, the inhomogeneous deposition of Li on the host leads to dendrite growth with safety hazards, limiting its potential application. In this study, we propose hierarchical Cu₂₊₁O nanowires with ultrathin Sn/Cu₆Sn₅ composites formed on copper foam, which were prepared in 90 min by a fully electrochemical wet process with high cycling stability. Cu₂₊₁O nanowires converted from Cu(OH)₂ offer a large surface area to distribute the surface charge uniformly with a low local current density, whereas the ultrathin Sn/Cu₆Sn₅ composite with a high affinity for Li induces uniform nucleation over the entire surface of the host without reducing the energy density. Consequently, the symmetric cell can be cycled for more than 3000 h at a current density of 0.5 mA cm⁻² with a low voltage hysteresis of 8 mV, confirming the enhanced stability of Li deposition. Furthermore, a full cell with a LiFePO₄ (LFP) cathode exhibited superior cycling stability and rate performance. This approach demonstrates a low-cost and time-saving industrially applicable process via a fully electrochemical wet method to regulate the harmless lateral growth of Li dendrites.