Owing to the high de/intercalation potential of anions on graphite cathode, dual-ion battery (DIB) has attracted much attention for advanced energy storage. Among various DIBs, Li//graphite (Li//G) configuration delivers the highest voltage to achieve the theoretically highest energy density due to the lowest Li-plating/-stripping potential. Unfortunately, the dendrite nature of Li anode brings a series of serious problems, fatally restricting the practical application of Li//G DIB. Herein, we for the first time propose fabricating artificial and robust a solid electrolyte interphase layer on Li anode to suppress Li dendritic growth during cycling and hence to improve the cyclic stability of Li//G DIB. As a result, a long-life Li//G DIB is assembled and achieved successfully with the enhanced and smoothed Coulombic efficiencies (CE). For example, the Li//G DIB exhibits a high capacity retention of 89.6% with an average CE of 97.8% and initial discharge capacity of 95.2 mAh g–1 over 500 cycles at 1 A g–1. This study points out a new possible strategy to enhance the energy-storage performance of Li//G DIB with high practicability.