A sustainable route from corn stalks to N, P-dual doping carbon sheets toward high performance sodium-ion batteries anode

High performance is indispensable for amorphous carbon materials toward sodium-ion batteries anode. Heteroatom doping has proved to be an effective strategy to improve the electrochemical performance of carbon-based materials. In this paper, N, P dual-doped carbon sheets (N, P-CS) from the rinds of corn stalks have been successfully synthesized via a hydrothermal reaction using the cheap (NH4)(2)HPO4 as nitrogen and phosphorus source. SEM and TEM images showed that the N, P-CS was composed of loose and stacked graphitic carbon sheets, which facilitated the penetration of electrolyte and ion diffusion. Higher ID/IG value (1.692) implied more defective sites on the surface of graphitic sheet to be generated after N and P co-doping, which combined with larger graphene layer distance (0.391 nm) contributed to the high performance of the N, P-CS. When used as anode for sodium ion batteries, it presents a specific capacity of 277mAh g(-1) after 100 cycles at 0.25C, and a specific capacity of 202 mAh g(-1) after 200 cycles at 1C. Even at a high rate of 5C, a stable specific capacity of 105 mAh g(-1) still could be delivered after 2000 cycles, suggesting an excellent cycle stability and superior rate capability. (c) 2018 Elsevier Ltd. All rights reserved.