A novel polyurethane-LiF artificial interface protective membrane as a promising solution towards high-performance lithium metal batteries

To construct highly stable Lithium (Li) metal batteries (LMBs), a polyurethane-LiF based artificial protective membrane (APM) is evenly coated onto LM anodes by a facile solution casting method. Owning to the good ionic conductivity and mechanical properties, APM acts as a physical protective isolation layer between electrolytes and LM to alleviate electrolyte decomposition and suppress Li dendrites. By applying the APM modification, the electrochemical performance of LM is dramatically improved. The Li | APM-Cu half-cell stably circulates 120 cycles with a high Coulombic efficiency of above 90% at a current density of 1 mA cm−2 and an area capacity of 1 mAh cm−2. The APM-Li based symmetric cell presents an ultralong life span of over 1500 h at an area capacity of 1 mAh cm−2and a current density of 0.5 mA cm−2. In full-cell tests, the APM-Li | LiFePO4 configuration maintains a high specific capacity of 120.4 mAh g−1 after 600 cycles with a superior capacity retention of 97.3% at 2C. Additionally, the extraordinary cyclability of APM-Li | Li4Ti5O12 full-cell demonstrates the effectiveness and versatility of APM. The scanning electron microscopy studies confirm the APM's suppression effects of Li dendrites. Therefore, this work provides a promising and affordable APM modification strategy to redeem highly stable LMBs.