Porous nitrogen doped carbon sphere as high performance anode of sodium-ion battery

The carbon material is regarded as the most promising anode candidate for sodium ion battery. In this paper, we found that the porous structure is a critical factor for the improving of carbon anode material. Porous structure is successfully fabricated in nitrogen doped carbon sphere (N-CS) via the mature template-assisted method and the sodium storage property of the porous nitrogen doped carbon sphere (P-N-CS) and N-CS is investigated. The results show that the P-N-CS possesses super rate capability of 155 mAh g−1 at 1 A g−1, which is much higher than that of N-CS (18 mAh g−1). In addition, the P-N-CS exhibits outstanding cycle stability with 206 mAh g−1 after 600 cycles at 0.2 A g−1 and the capacity of N-CS is only 96 mAh g−1 at the same condition. The super electrochemical performance of P-N-CS could be attributed to the high content of pores. Moreover, the high content of pyridinic and graphitic N could facilitate the transfer of sodium ion and electron.