Nitrogen and phosphorus co-doped 3D hierarchical porous carbon network with highly-reversible performance in sodium storage

In this paper, synthesis of nitrogen and phosphorus co-doped 3D hierarchical porous carbon network (NP–CN) with superior electrochemical performance in sodium-ion battery anode material was reported. In terms of structure, 3D network structure can fully alleviate the stress generated during charging and discharging, while hierarchical porous structure provides more electron and ion transmission channels, which facilitates rapid transfer of charge. Meanwhile, doping of nitrogen and phosphorus can increase defect sites of material to promote sodium ion adsorption. In addition, nitrogen can enhance conductivity of material and phosphorus can be inserted into carbon lattice to enlarge interlayer spacing, beneficial to the intercalation and deintercalation of sodium ions. Based on above advantages, NP-CN possesses 315 mAh g⁻¹ at 100 mA g⁻¹ after 200cycles in sodium-ion battery. Furthermore, the method is simple and raw material is easy to obtain, making NP-CN have better practical value.