Lithium Electrodeposition in the Presence of Surfactants

Abstract

The aim of this work is to study the possibility of suppressing the metallic lithium dendrite formation during the operation of lithium secondary batteries, including those with a metallic lithium anode. The electrochemical deposition of lithium on copper and lithium substrates in the presence or absence of two surfactants, cetyltrimethylammonium bromide and hexadecylpyridinium bromide, is studied by the current transient and electrochemical impedance measurements. A typical lithium-ion battery electrolyte based on lithium hexafluorophosphate in the mixture of ethylene carbonate and diethyl carbonate is used. The presence of the so-called SEI (solid electrolyte interphase) layer on the electrode surface is shown to have a significant effect on the electrodeposition process. It is also shown that the mechanism of lithium electrodeposition on copper and lithium substrates is different. It can be assumed that the observed effect of surfactants on the dendrite formation is associated not with the adsorption of surfactants on lithium and blocking the growth of deposits, but with the surfactant effect on the properties of the SEI layer formed at these substrates.