The effects of a solid electrolyte interface (SEI) additive, triacetoxyvinylsilane (VS), on the electrochemical performance of a lithium metal secondary battery were investigated. When  VS was added to the electrolyte, no lithium dendrite on the lithium metal surface after precycling was observed and thereby the lowest interfacial resistance of the unit cell  could be achieved. With these reasons, the capacity of the unit cell based on the electrolyte containing  VS could maintain about 80% of the initial capacity after  at a high charge/discharge current density (C/2, ).