The effect of Mg(ClO4)(2) and HF acid in 1 M LiPF6(/EC + DEC + DME electrolyte oil the cycle behaviors and the surface characteristics of the lithium electrode were investigated. The morphology of the electrode is greatly improved using Li-Mg co-deposition and HIP acid, and results in the enhancement of the cyclability observed by electrochemical measurement. The scanning electron microscopy images of the electrode surface show densely deposited lithium-magnesium alloy particles with a hemispherical shape on the entire surface of the electrode. The improved coulombic efficiency was attributed to the synergistic effect due to the formation of Li-Mg alloy and LiF caused by Li-Mg co-deposition and HF to the electrolyte, respectively. (c) 2007 Elsevier Ltd. All rights reserved.