In this study, the formation of an artificial primary solid electrolyte interphase on a fresh Li surface, via reaction with 1-pentylamine (PA), is reported, allowing removing the influence of the metal electrode’s prior history. Electrochemical impedance spectroscopy, galvanostatic cycling, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) are used in order to investigate the effect of PA as solid electrolyte interphase precursor on Li metal. It is shown that pretreating native SEI-free Li metal surfaces with 1M PA in n-pentane sharply decreases the electrode impedance and overpotential with respect to the treatment with only n-pentane. The treatment with 1M PA in n-pentane results in surface roughening, but no increase of dendrite formation upon cycling. However, the use of higher PA concentration (5M) increases impedance and overpotential and leads to dendrite growth.