A single-crystal copper (111) current collector for anode-free lithium batteries

Anode-free lithium (Li) batteries that function via direct Li plating/stripping from cathodes have led to a surge of interest in metallic lithium as an ideal negative electrode. Despite its great promise, its practical use has been hampered by dendritic growth of Li metal, which results in low coulombic efficiencies and cell shorting. In addition, such dendritic growth of Li makes a larger unoccupied space in the battery, which causes dramatic reduction in volumetric energy density. We report that Li plating is a collective motion of Li adatoms influenced by the crystallographic orientation of the Cu substrate, and that Li adatoms can be redistributed by interacting with individual Cu grains via surface migration. By comparing centimeter-sized single-crystal Cu(111) and Cu(410) foils, we found that Cu(111) foil inhibits dendritic growth of metallic Li and that, per our modeling, this is likely due to the near-zero migration barrier of Li adatoms. We suggest that understanding, and ‘controlling’ the Li adatom surface migration ‘behavior’ opens a new avenue for achieving high-performance anode-free Li batteries.