Oxidative-polymerization and deoxygenation of mixed phenols to faradaic-oxygen modified mesoporous carbon and its supercapacitive performances

摘要

To find the effect of phenols type on the physical/chemical characteristics and their supercapacitor performances of the derived carbons. Herein, three types of diphenol isomers (catechol, resorcinol and hydroquinone) mixed with phenol (molar ratio of 1:1) were employed as precursors to prepared porous carbon by oxidation polymerization and deoxygenation method. Systematically investigation shows that the derived three carbons all ahcieves a disordered mesoporous structure, while, hydroquinone mixed with phenol derived carbon (HPMC973) owns higher surface area of 1758 m(2)/g than that of catechol mixed with phenol derived CPMC973 of 1303 m(2)/g and resorcinol mixed with phenol derived RPMC973 of 1452 m(2)/g, larger pore volume of 1.94 cm(3)/g (vs. CPMC973 of 1.09 and RPMC973 of 1.25 cm(3)/g) and more open structure with larger mesoporosity of 97.3% vs. CPMC973 (86.1%) and RPMC973 (96.1%) resulted from its unique spatial structure enabling the formation of highly cross-linked structure. The residual oxygen species in the three carbons mainly exist in the forms of -C = O and -COO-. Benefited from the highly open-accessed mesoporosity and rich electroactive oxygenic species, the HPMC973 electrode exhibits a high capacitance of 418 F/g@0.5 A/g (vs 306 F/g for CPMC973 and 302 F/g for RPMC973) in 1.0 M H2SO4, the capacitance can be maintianed at 325 F/g@20 A/g, showing a superior rate capability with the retention of 77.8%. The fabricated symmetric supercapacitor based on HPMC973 in 1.0 M Li2SO4 delivers a ultrahigh specific energy of 27.9 Wh/kg@895 W/kg (vs. 16.9 Wh/kg for RPMC973 and 15.8 Wh/kg for CPMC973) and achieves an excellent cycling stablity with near 100% capacitance retention after 10 000 cylces at large current density of 20 A/g, offering a great potential for energy storage application. The current research provides a facile method for the fabrication of mesoporous carbon without using the harmful formaldehyde thus affords a promissing candidate for wide application in sorption, catalysis, energy storage, and etc.