Preparation of N-doped carbon material derived from porous organic polymer as an active center to growth nickel cobalt phosphide for high-performance supercapacitors

In this study, nitrogen-doped porous carbon materials derived from Azo-bridged calix[4]resorcinarene porous organic polymer were synthesized via pyrolysis at various temperatures. Notably, this work represents the first successful fabrication of nitrogen-doped carbon materials utilizing the Azo group (N=N) as a nitrogen source. This novel approach introduces diverse nitrogen configurations into the carbon matrix, crucial for enhancing material properties. Among the synthesized materials, nitrogen-doped carbon derived at 800 °C (N-C-800) exhibited exceptional characteristics including a high content of graphitic nitrogen, substantial specific surface area, hierarchical porous structure, and favorable conductivity, rendering it suitable for supercapacitor applications. N-C-800 demonstrated a remarkable specific capacity of 340 F g⁻¹. Furthermore, the presence of pyridinic‑nitrogen functionalities in N-C-800 facilitated the anchoring of nickel cobalt phosphide nanowires, fostering a strong interaction between nitrogen and the metal. The resulting composite, Ni₁Co₂P@N-C-800, served as a positive electrode and showcased superior specific capacity of 1275 F g⁻¹ with an impressive capacitance retention of 87 % over 1000 cycles at 1 A g⁻¹. Additionally, an asymmetric supercapacitor configuration, Ni₁Co₂P@N-C-800//N-C-800, utilizing both N-C-800 and Ni₁Co₂P@N-C-800 electrodes, was simulated, delivering an energy density of 50.44 Wh kg⁻¹ at a power density of 799 W kg⁻¹. This work underscores the potential of facile synthesis routes for generating novel electrode materials with enhanced electrochemical efficiency, offering promising avenues for advanced energy storage applications.