Nitrogen-doped 3D carbon hybrids based on modified lignin as sulfur host for high-performance lithium-sulfur batteries

Constructing a sulfur host with strong adsorption and catalytic conversion of polysulfides is significant in improving the electrochemical performance of lithium-sulfur batteries. In this work, we obtained nitrogen-doped 3D carbon hybridized materials (lignin porous carbon/carbon nanotubes, LPC/CNTs) by self-assembly and in situ activation methods. This is the first time to achieve nitrogen-doped carbon hybrids by melamine modification lignin as raw material. The results show that the construction of the nitrogen-doped 3D carbon hybridization network is highly correlated with the modification treatment of lignin. As sulfur host material, it can reach a specific capacity of 1300.18 mAh g(-1) at 0.1 C for the first time and still has a specific capacity of 582.84 mAh g(-1) at 1 C for 400 cycles. In addition, carbon hybridized materials show excellent rate performance and high current adaptability in the rate performance test compared with the carbon materials prepared from unmodified lignin. The excellent electrochemical performance is mainly attributed to the synergistic effect within the 3D interconnection network, which enhances the physical confinement and chemical adsorption of polysulfides, as well as the catalytic conversion. This work provides new insights into biomass application in the sulfur hosts of lithium-sulfur batteries.