Lignin-derived Lithiophilic Nitrogen-doped Three-dimensional Porous Carbon as Lithium Growth Guiding Layers for Lithium-metal Batteries

The growing demand for high-performance next-generation lithium (Li)-based batteries has brought Li-metal anodes into the spotlight, due to their high theoretical capacity (3,860 mAh g-1) and low electrochemical potential (-3.04 V vs. SHE). However, the practical application of Li-metal anodes faces formidable challenges, primarily associated with dendritic Li growth resulting from non-uniform ion flux. Although previous studies utilizing carbonaceous materials having pores and lithiophilic atoms have demonstrated powerful performances, the complex process involving pore creation and doping with heteroatoms still has limitations in terms of cost-effectiveness. This study introduces a lithiophilic nitrogen (N)-doped three-dimensional (3D) porous carbon (NLC) by simply reusing and carbonizing NH2-functionalized lignin (NL), an eco-friendly biopolymer derived from waste wood generated during the pulping process. The NLC offers macro-porous spaces with a rich array of N-doped sites, capable of accommodating and guiding Li deposition to facilitate uniform Li growth. The results demonstrate the effectiveness of the NLC as the Li growth guiding layer in Li-metal batteries. A full cell incorporating the NLC as a Li growth guiding layer, with NCM811 as cathodes, exhibits a remarkable capacity of 145. 57 mAh g-1 even at a high C-rate of 5C and capacity retention of 90.3% (167 mAh g-1) after 150 cycles at 1C. These findings represent significant advancements compared to conventional Li-metal batteries.