Hierarchically Porous N, P-Codoped Carbon Materials for High-Performance Supercapacitors

Carbon materials with heteroatom doping have drawn enormous attention as electrode materials owing to their tunable surface properties and adjustable structures, yet their facile obtainment has been mostly hindered by the complex synthesis routes and low heteroatom-doping efficiency. Herein, we showcase the simple synthesis of N, P-codoped carbon nanomaterials (NP-C) with beneficial pore hierarchy by applying the dehalogenation of poly(vinyl dichloride) (PVDC) by KOH at room temperature and high-efficiency functionalization of the remaining carbon skeleton using melamine and NaH2PO2. The concentration and configuration of N and P heterodopants can be simply tuned by altering the calcination temperatures. The resultant material prepared at 700 °C delivers superior capacitive performance: a high specific capacitance (Cs) of 367.5 F g–1 at 0.5 A g–1 and a capacity retention of ∼95% after 10 000 cycles at 10 A g–1. As analyzed by the Dunn method, ∼27.8% of the complete capacitance is contributed by the pseudocapacitive charge storage, thanks to the high-content N (∼6.3 atom %) and P (∼1.3 atom %) doping. Our facile preparation method can be potentially extended to the synthesis of more binary and ternary heteroatom-doped carbon nanomaterials for broad electrochemical applications.