A porous carbon based on the surface and structural regulation of wasted lignin for long-cycle lithium-ion battery

Lignin, as the second most abundant source in nature, is considered as a good precursor for hard carbon. However, direct carbonization of pure lignin leads to low surface area and porosity. Herein we develop a method to prepare lignin-based porous carbon by a self-template method assisted with surface modification. The oxygen-containing functional groups are introduced to regulate the surface chemistry of lignin. And the metal ions are chosen to coordinate with the oxygen-containing group in the lignin, which can form the carbonates to act as the self template to regulate the pores structure. The aromatic skeleton of lignin can also disperse the metal ions to bring uniform pore-forming sites. The results show that the carbonized lignin modified by chloroacetic acid (CCL) shows mesopores with surface area of 233.4384 m2 g-1. As anode for lithium-ion batteries (LIBs), the CCL shows a specific capacity of 500 mAh g-1 at 50 mA g-1. The capacity retention was 99 % after 1000 cycles at 1000 mA g-1, which are superior to most reported carbon anode. This work proposes a low-cost anode for LIBs and put forward a regulation strategy for bio-mass carbon. Besides, it would reduce the discard of lignin and alleviate the pollution.