Preparation of porous lignin-derived carbon/carbon nanotube composites by hydrophobic self-assembly and carbonization to enhance lithium storage capacity

The high-value utilization of green renewable nature lignin is an effective way to improve the economic feasibility of the lignocellulosic refine industry. Especially, the porous lignin-derived carbon (PLC) with high surface area prepared by activation is promising for application in energy storage field. However, the low graphitization degree, high micropore volume and poor structural stability of PLC have been the major obstacle for further application as the energy storage materials such as lithium ion batteries. Here, a highly dispersed lignin and carbon nanotube composites (Lignin/CNTs) were firstly prepared by hydrophobic self-assembly process based on pi-pi interaction, and then carbonized to obtain PLC/CNTs materials with layered structure supported by carbon nanotubes. The intervention of carbon nanotubes can improve the conductivity and structural stability of PLC, especially the microstructure, which provides a transmission channel and active site for the storage of lithium ion. Compared with PLC (900 degrees C, K2CO3 activation), the resulting of PLC/CNTs possess lesser microporous, a large number of mesoporous channels and higher graphitization. Therefore, PLC/CNTs exhibited excellent lithium storage capacities, such as the initial coulombic efficiency increased by ca.25% and the reversible capacity increased by 24% than that of PLC. This process provides a simple method for the dispersion of CNTs, and provides basic data for the high-value of industrial lignin. (C) 2019 Published by Elsevier Ltd.