Electrochemical Characteristics of Lithium Metal Anodes with Diamond Like Carbon Film Coating Layer

Abstract

To overcome the poor electrochemical characteristics of lithium metal anodes due to the dendrite formations, diamond like carbon (DLC) films were deposited onto the surface of lithium metal by radio frequency-plasma enhanced chemical vapor deposition (CVD) technique using acetylene gas as carbon precursor. The substrate temperature was selected as the main experimental parameter to control the bonding characteristic (sp2/sp3 ratio) of the films. The presence of diamond like structures was confirmed by Raman and Fourier transform infra red spectroscopy. The DLC coated lithium metal was then characterized as an anode material for lithium secondary batteries. The results showed that the DLC coated lithium metal anodes exhibited better electrochemical characteristics in terms of higher specific capacity and smaller interfacial impedance. These improved characteristics were attributed to the presence of DLC film coating which might suppress the dendrite's formation by protecting the lithium metal surface from the direct contact with the electrolyte.