Lithiophilic LiC6 Layers on Carbon Hosts Enabling Stable Li Metal Anode in Working Batteries

Lithium (Li) metal-based battery is among the most promising candidates for next-generation rechargeable high-energy-density batteries. Carbon materials are strongly considered as the host of Li metal to relieve the powdery/dendritic Li formation and large volume change during repeated cycles. Herein, we describe the formation of a thin lithiophilic LiC6 layer between carbon fibers (CFs) and metallic Li in Li/CF composite anode obtained through a one-step rolling method. An electron deviation from Li to carbon elevates the negativity of carbon atoms after Li intercalation as LiC6 , which renders stronger binding between carbon framework and Li ions. The Li/CF | Li/CF batteries can operate for more than 90 h with a small polarization voltage of 120 mV at 50% discharge depth. The Li/CF | sulfur pouch cell exhibits a high discharge capacity of 3.25 mAh cm-2 and a large capacity retention rate of 98% after 100 cycles at 0.1 C. It is demonstrated that the as-obtained Li/CF composite anode with lithiophilic LiC6 layers can effectively alleviate volume expansion and hinder dendritic and powdery morphology of Li deposits. This work sheds fresh light on the role of interfacial layers between host structure and Li metal in composite anode for long-lifespan working batteries.