Uniform Li Deposition Sites Provided by Atomic Layer Deposition for Dendrite-Free Lithium Metal Anode.

Dendrite growth and instability of solid electrolyte interphase (SEI) resulting from nonuniform lithium (Li) nucleation severely prevents Li metal battery from practical applications. In this paper, atomic layer deposition (ALD) is used to deposit ultra-thin conformal ZnO layer (at a low content of 5.96%) on the surface of carbon fiber to form a free-standing framework Li host material without uncontrollable dendrites. Compared with the liquid deposition process, the ALD method can achieve homogeneous and conformal ZnO coating and excellent lithiophilicity of the carbon fiber, guiding molten Li infusion into the carbon fiber skeleton to obtain Li/C composite electrode with a flat surface, thereby minimizing the effective current density. More importantly, the converted LiZn alloy can provide uniform and numerous nucleation sites for Li and guide synchronous growth of Li metal along carbon fibers, displaying a dendrite-free morphology after large-current and long-term deposition/dissolution cycling. As a result, the ALD ZnO-modified carbon fiber/Li (Li/C-ALD) exhibits significantly better cycle and rate performances than the liquid deposition ZnO-modified carbon fiber/Li composite anode. The electrodes display an ultralong lifespan up to 400 cycles at 3.0 mA/cm2, as well as a high rate performance (with deposition overpotential of 338 mV at 25.0 mA/cm2) at a high Li deposition areal capacity of 5.0 mAh/cm2.