Lithiophilic hyperbranched Cu nanostructure for stable Li metal anodes

Porous copper (Cu) current collectors are regarded as a promising host for stabilizing lithium (Li) metal anodes but suffer from uncontrollable Li metal deposition due to the intrinsic lithiophobic nature of Cu. This study proposes a vertically aligned Cu host with hyperbranched CuxO nanostructure to provide lithiophilic nucleation sites for homogeneous Li metal deposition. Specifically, the vertically aligned Cu nanostructure dramatically reduces the local current density and brings homogeneous Li-ion flux. The lithiophilic hyperbranched CuxO nanostructure with a low nucleation barrier could induce homogeneous Li nucleation and growth. As a result, the Cu@CuxO nanostructured host exhibits a low nucleation overpotential of 44.3 mV and achieves highly electrochemical reversibility with high Coulombic efficiency of 98.33% in a half-cell. The Cu@CuxO nanostructured electrode is capable of working under different current densities varying from 0.5 to 5 mA/cm(2) in a symmetric cell. The assembled full cell coupling of the Li/Cu@CuxO composite anode with the LiFePO4 cathode manifests stable long-term cycling life at 1 C. This study elaborates on the synergistic effect of electrode structure design and interfacial chemistry modification to regulate the Li deposition/dissolution behavior, thus exhibiting remarkable electrochemical performances for next-generation Li-metal batteries.