In this study, 2-fluoro-5-iodopyridine (2-F-5-IPy) was used as an electrolyte additive, which can not only protect the negative electrode effectively by forming a stable SEI, but also convert dead lithium into active lithium. Benefits from this are a capacity retention of a Li‖LiFePO4 cell after 300 cycles from 36.5% to 89.4%, and the symmetrical cell can work stably for more than 800 hours. Therefore, the addition of 2-F-5-IPy can effectively improve the performance of lithium metal batteries.