Atomic layer deposition for improved lithiophilicity and solid electrolyte interface stability during lithium plating

Abstract

Uneven deposition and stripping of Lithium (Li) can lead to dendrite growth and instability of solid electrolyte interphase (SEI), which severely prevents the Li metal battery from practical applications. In this paper, atomic layer deposition (ALD) method is used to alter the lithiophilicity of carbon fiber network by depositing ultra-thin conformal ZnO layer at a low mass loading (5.9 ​wt%). The thin layer ZnO by ALD could provide uniform Li nucleation sites and guide Li deposition along the carbon fibers without formation of dendrites, and release Li from top of the electrode without formation of dead Li during dissolution. As a result, the ALD ZnO-modified carbon fiber/Li (ALD/C–Li) composite anode can cycle stably at a large current density as high as 15 ​mA/cm2 giving low overpotential (105 ​mV) and long-running lifespan with stable stripping/plating profiles nearly 500 cycles at 5 ​mA/cm2. Tests of X-ray photoelectron spectroscopy (XPS) combined with argon ion etching show that the ALD/C–Li anode can effectively stabilize the SEI with a negligible increase in thickness after 100th cycle, while that of bare Li electrode doubles under the same cycling conditions. The full cell with LiFePO4 cathode also shows a much low hysteresis at 2 ​C over 300 cycles. The strategy developed in this work provides a novel alternative to Li anodes with long lifespan and opens up a new avenue for Li metal batteries with high energy density and high power density.