Constructing porous lignin-based carbon nanofiber anodes with flexibility for high-performance lithium/sodium-ion batteries

Lithium/sodium-ion batteries have been widely studied as energy storage power sources because of their long cycle life and high energy density. Lignin, which is environmentally friendly, inexpensive, and has a high carbon content, is considered one of the most promising raw materials for anodes. Hence, in this study, a porous lignin-based carbon nanofiber anode was obtained using gas–electric blending. The prepared anode is flexible, self-supporting, and can be directly used without any binders in Li/Na-ion batteries. It showed excellent first reversible specific capacity of 1783.8 mAh g -1 at 0.2 C current density and maintained a specific capacity of 1429.7 mAh g -1 after 50 cycles in the Li-ion battery. Even at a high current density of 2 C, it exhibited a high reversible specific capacity of 1135.4 mA h g -1 in the first cycle and retained 1064.7 mAh g -1 after 100 cycles. Furthermore, it also exhibited excellent specific discharge capacity, stable cycle performance, and high rate performance in Na-ion batteries. This study demonstrates that lignin has broad application prospects as a high-performance energy storage material. 1. A porous lignin-based carbon nanofiber anode is obtained by using a gas-electric blending technology. 2. This lignin-based carbon nanofiber anode has flexibility and self-supporting characteristics. 3. The LCNF/G-2 anode has excellent performances in both lithium and sodium-ion batteries.