Effect of surface topography on dendritic growth in lithium metal batteries

Lithium (Li) metal, which has the advantages of high theoretical capacity, low redox potential, and low density, is considered an ideal anode material for next-generation battery systems. However, the dendritic morphology of Li-metal electrodeposition during the charging process remains challenging because it results in active Li depletion, poor cycling performance, and safety issues. Herein, the effect of surface topography on dendrite growth was quantitatively revealed by an electro-chemo-mechanical phase-field model. The surface topography of the Li-metal battery was measured and quantified using the arithmetic mean roughness (Ra), root mean square roughness (Rq), impulse factor (Rp), skewness, and kurtosis. The simulation results revealed that the arithmetic mean height of the bare electrode and the height of the highest tip compared to the average height were highly correlated with dendrite growth. It was also demonstrated that controlling the surface topography, applied voltage, and external pressure can effectively suppress dendritic growth. Furthermore, the exposed surface of the electrode generated by the size difference or misalignment of the electrodes induced considerable dendrite growth. We believe that our quantitative analysis provides guidance for processing the surface roughness of practical Li-metal batteries.