双离子液体基多孔炭的制备与电化学性能

Nitrogen, phosphorus and sulfur co-doped porous carbons(PCs) were prepared with a protic ionic liquid 1-hydrogen-3-butylimidazolium hydrogen sulfate(HVImHSO₄) as precursor and 1-butyl-3-methylimi-dazolium hexafurophosphate(BMImPF₆) as assistant through one-step carbonization process at 1000℃ in nitrogen atmosphere. The PCs were characterized by nitrogen adsorption-desorption, scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), Raman spectroscopy, thermo-gravimetric analysis(TGA) and X-ray photoelectron spectroscopy(XPS). The results showed that the PCs mainly had micro pores and the specific surface area could be up to 1111 m²/g under m(BMImPF₆)/m(HVImHSO₄)=0.4. The amorphous and disordered graphitic layers were dominant in PCs. Nitrogen bonding state was mainly N-Q(N substituted groups of aromatic graphite structure), phosphorus was mainly in O-P type groups, and sulfur was attributed to C-S-C of thiophene-type sulfur. Meanwhile, the capacitance of PC-BMImPF₆-0.5 was 138 F/g at 0.5 A/g and 100 F/g at 10 A/g, the retention ratio was 95.8% after being cycled for 10000 times at 2 A/g in the electrolyte of 6 mol/L KOH. A simple and easy method for preparation of N, P and S co-doped PCs from ionic liquids has been provided, and the PCs have a certain extent application prospect in supercapacitor electrode materials.