Effect of Structure on the Electrochemical Performance of Nitrogen- and Oxygen-Containing Carbon Micro/Nanospheres Prepared from Lignin-Based Composites

Nitrogen- and oxygen-containing carbon micro/nanospheres (C PAN and C PNA ) were prepared by direct pyrolysis of lignosulfonate/polyaniline and lignosulfonate/poly( N -ethylaniline) composite spheres at the temperature of 700 °C. The two type lignin-based composite spheres were prepared by an in situ polymerization of aniline and N -ethylaniline in the presence of lignosulfonate, respectively. The carbon spheres were investigated by thermal gravimetric analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy and were used as anodes for lithium ion batteries. The two carbon spheres showed different electrochemical performances due to their different surface functional groups and structures. The C PAN carbon nanospheres had better electrochemical performance as anodes for lithium ion batteries than that of C PNA carbon microspheres. The first charge capacity and discharge capacity of the C PAN nanospheres at a current density of 60, 100, and 200 mA g –1 exhibited a discharge capacity of 1450, 1094, and 770 mAh g –1, respectively, and a charge capacity of 707, 698, and 446 mAh g –1, respectively. Furthermore, it still owned a high discharge capacity at a current density of 60, 100, and 200 mA g –1 of 526, 431, and 338 mAh g –1, respectively, after 20 cycles.