Nitrogen-doped cotton stalk porous carbon composite as anode material for Lithium-ion battery

Abstract

• The synergistic mechanism of ZnCl 2 and urea was systematically studied for LIB anode. • Porous carbon with high heteroatomic content(N-AC) has good electrochemical performance. • Development of pore structure is the basis for excellent electrochemical performance. • The increase of heteroatom content and layer spacing is the reason for the performance enhance. In this study, the raw material of cotton stalks, N source of urea, and activator of ZnCl 2 were used to prepare high N-doped cotton stalk activated carbon (N-AC) and exploring the synergistic mechanism of activator and dopant on electrochemical performance improvement. Addition of ZnCl 2 promoted the formation of mesopores, but urea inhibited the development of pore structures. In addition, the development of pore structure was the basis for excellent electrochemical performance. The co-modification promotes the retention of heteroatoms and the expansion of interlayer spacing on the basis of retaining the three-dimensional pore structure, which is also the main reason to obtain the higher electrochemical performance. N-AC, an LIB anode material, still maintained a specific capacity of 504.1 mAhg −1 after 100 cycles at current density of 0.1 Ag −1 . Under the high current density of 2 Ag −1 , N-AC showed a specific capacity of 250.32 mAhg −1 , which had good cycle performance and rate performance. This study discussed the mechanism of two modification methods to improve electrochemical performance, which provided a theoretical basis for future research.