Hierarchical-structure and high-modulus aramid nanofiber membrane protective layer achieving high-performance lithium metal anode

Uniform lithium deposition and a stable solid electrolyte interface (SEI) film are crucial for realizing long-term stable operation of lithium metal batteries. Herein, aramid nanofiber (ANF) membrane with abundant amide bonds and hierarchical structure as an artificial solid electrolyte interface (SEI) was constructed through a simple two-step assembly strategy, which can effectively improve the interfacial compatibility and inhibit the growth of Li dendrites. A large number of polar amide bonds in ANF films can serve as anchor points to interact with Li+. The layered structure and hierarchical porosity of ANF films exhibits significantly improved mechanical strength and ability to suppress dendrites. Therefore, the constructed ANF membrane can homogenize the lithium flux during lithium plating/stripping process, inhibit the formation of hot spots, and promote the formation of a uniform SEI layer under these synergistic effects. The ANF modified Li (ANF@Li) anodes exhibit significantly improved electrochemical performance, stable cycling for 2500 h at high current density (10 mA cm−2) and 2500 h at high capacity (10 mAh cm−2). In addition, ANF@Li anodes showed a long life over 2800 h at 5 mA cm−2 and 10 mAh cm−2, which enables the ANF@Li anode to be the promising candidate for the next generation of high-power-density and high-energy–density batteries.