Pore-size-tunable nitrogen-doped polymeric frameworks for high performance sodium ion storage and supercapacitors

Abstract

Sodium-ion batteries (SIBs) is considered as a promising alternative to lithium-ion batteries. Supercapacitors (SCs) are receiving great attention for their significantly higher power density than batteries and prolonged cycle life. Herein, SIBs and SCs based on N-doped amorphous multi-size pores dominated polymeric frameworks were fabricated and examined. The enlarged interlayer spacing and multi-size-pore dominated interconnected architecture with high specific surface area, high pore volume and high N content optimize the electrochemical performance of N-PPF-20. As an anode material, N-PPF-20 exhibited a sodium ion storage capacity of 432.2 mAh g⁻¹ at a current density of 0.05 A g⁻¹, while maintaining a reversible capacity of 61.1 mAh g⁻¹ at an ultrahigh current density of 20 A g⁻¹. Additionally, a specific capacity of 158.3 mAh g⁻¹ at 1 A g⁻¹ was obtained after 1000 cycles, indicating an excellent cycling stability. When tested as an electrode material for SCs, N-PPF-20 delivered a high specific capacitance of 438.7 F g⁻¹ at 0.1 A g⁻¹, and a specific capacitance of 111.2 F g⁻¹ was achieved even at a high current density of 10 A g⁻¹. Meanwhile, a long-term cycling life test demonstrated a specific capacitance of 120 F g⁻¹ at an ultrahigh current density of 10 A g⁻¹ after 10,000 cycles.