Thin and Homogenous Surface Functionalization of Lithium Metal Anodes by Defined Molecular Treatment

The safe and stable utilization of lithium metal as an anode in rechargeable batteries is still a major challenge. One way to improve the performance of lithium anodes is the modification of its surface. Here we report two possible methods for lithium surface modification using a combination of tris(N,N-tetramethylene)phosphoric acid triamide and an alcohol for dip coating. The coatings lead to a thin and homogenous surface layer on the electrodes which causes diminished cell resistance and enhanced life time in symmetrical transference cells as well as enhanced capacity retention in Li-S batteries. Surface analyses by XPS and SIMS prove the incorporation of phosphorus and nitrogen into the SEI and the presence of highly lithium ion conductive Li3N.