Three-dimensional porous carbon doped with N, O and P heteroatoms as high-performance anode materials for sodium ion batteries

Porous carbon (PC) materials are the excellent alternative to anodes of high performance sodium ion batteries (SIBs). However, most PC materials are prepared with complicated and multi-step template method, which limits the mass production. Herein, we present a simple and repeatable calcination approach to synthesize three-dimensional porous carbon (3D-PC) materials using poly(p-phenylenediamine) hydrogel as precursor. N, O and P heteroatoms are successfully introduced into 3D-PC to provide more sodium storage sites. The obtained 3D-PC delivers high sodium storage capacity of 332 mAh g−1 at 50 mA g−1 and the reversible capacity still retains 139 mAh g−1 at 10 A g−1. Moreover, 3D-PC also shows ultralong cycling life, the stable capacities of 212 mAh g−1 and 120 mAh g−1 after 1000 cycles even at the high current density of 0.5 A g−1 and 5 A g−1, respectively. These results illustrate that 3D-PC electrode displays great rate capability and excellent cycling stability, which would be ascribed to surface-dominated sodium storage mechanism according to quantitative analysis. This method is low cost and effective for preparing high-performance porous carbon anodes for SIBs.