Phosphorus-doped pitch-derived soft carbon as an anode material for sodium ion batteries

A pitch-derived soft carbon is successfully prepared by easy-accessible pyrolysis process in this work. The electrochemical performance of the acquired soft carbon can be improved via doping phosphorus. We found that the phosphorus doping can increase layer spacing and defects of soft carbon, which improved the capacity of soft carbon significantly. The cell's initial reversible capacity of the phosphorus-doped pitch-derived soft carbon is as high as 251 mAh g−1, the capacity retention has been kept at 80.1% after 200 cycles. Herein, phosphorus doping is an effective way to improve the electrochemical performance of the pitch-derived soft carbon while phosphorus doped soft carbon is a promising candidate as an anode material for sodium ion batteries.