Coupling a Three-Dimensional Nanopillar and Robust Film to Guide Li-Ion Flux for Dendrite-Free Lithium Metal Anodes.

Lithium metal batteries with high theoretical capacity critically suffer from low cycling stability and safety issues mostly due to lithium dendrites. Regulating the Li-ion conduction and Li deposition is essential to achieve dendritic-free Li metal anodes. Herein, a synergistic strategy that combines a 3D nanocopper layer and a robust polymer protective layer is proposed. The 3D nanocopper layer in situ formed on the Li surface could achieve a uniform electric field distribution and contribute to reducing the nucleation barrier for Li deposition and refining the grain size of Li crystallites. Meanwhile, the Li-Nafion film with high Li-ion conductivity and good flexibility was used as a protective layer to provide homogeneous ion distribution and adapt to the volume change during the Li deposition. Consequently, the NCuLi∥LiCoO2 full cells exhibited outstanding cycling stability (a capacity retention of 90% over 500 cycles). Our results indicate that the synergistic control of Li-ion conduction and Li deposition is a promising method to achieve dendritic-free Li metal anodes.