Synthesis of Hierarchically Porous Nitrogen-Doped Carbon for Sodium-Ion Batteries

In this work, a facile synthetic strategy is developed for the preparation of nitrogen-doped (N-doped) hierarchically porous carbon materials. During the preparation process, sodium citrate and urea serve as carbon and nitrogen sources, respectively, without any template or additional activation reagents. Both the microstructure and nitrogen dopant content of the porous carbon can be tuned. The as-prepared porous carbon materials are tested as anodes in sodium-ion batteries. The porous N-doped carbon prepared at 650 degrees C shows a high reversible capacity of 305.7 mAhg(-1) at a current density of 0.1 Ag-1. Even at a higher current density of 8.0 Ag-1, a specific capacity of 164.5 mAhg(-1) is obtained. After 500 cycles, the specific capacity of the electrode remains as high as 219 mAhg(-1) at a current density of 1.0 Ag-1. This synthetic strategy provides a simple and efficient approach for preparing heteroatom-doped porous carbon in energy storage and other fields.