Phenolic Resin Based Nanoporous Carbon Materials: Self-activation Preparation, Adjustion And Performance

In this thesis,we prepared N,S-containing phenolic resins and alkoxyl-submitted phenolic resins,and further prepared porous carbon materials with uniform micropores by direct carbonization of the as-prepared resins.Due to the mono-dispersed K+ and different sized alkoxyl groups,we achieved the accuracy adjustment of micropore size.The relation between the microporosity and alkoxyl groups is studied.We also investigated the capacitive performance of the prepared carbon materials.1.Ultra-microporosity and heteroatom-doping have been proved to be desired for carbon electrode materials of advanced supercapacitors.In this section,dual N,S-doped carbon materials with high-developed ultra-micopores?⁰.70 nm?are prepared by direct carbonization of potassium salts of 3-amionphenol-3-mecaptophenol co-resin.The morphology,structure and surface properties of the carbon materials are investigated by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,N2 adsorption,X-ray photoelectron spectroscopy?XPS?,and Energy dispersive spectroscopy?EDS?.The potassium ions mono-dispersed in phenolic resins as a form of –O-K+ deliver a homogenous ?in-situ self-activation?,thus created developed ultra-microporosity with high uniformity,connectivity and short pore length.It was found that the reactant ratio of phenols play an important role on the microscopy morphology,pore texture and heteroatom-doping of carbon materials.Typical microporous carbon and micro-meso hierarchical porous carbon materials are prepared at controllable ration of 3-aminophenol and 3-mecaptophenol,respectively.2.The capacitive performance of the prepared N,S co-doped carbon materials are investigated in KOH and H₂SO₄ electrolytes.Due to the synergy effect of tailored ultra-microporosity and N,S,O-doping,the prepared carbons give good capacitive performance,including high specific capacitance,good power capability and long cycle stability.The SNC-3:1-600 carbon shows a high specific capacitance of 250 F g^-1,good capacitance retention of 61% in the range of 0.2²0 A g^-1,low relaxation time constant of 0.71 s in KOH electrolyte.The present preparation strategy is attractive and inspiring for preparation of tunable N,S-doped carbon materials for advanced supercapacitors.Due to the larger ions of H₂SO₄ electrolyte and lower conductivity,the prepared carbon materials show much poorer capacitive performance in H₂SO₄ electrolyte compared to those in KOH electrolyte.3.Accurate adjustment of micropore size of carbon materials is crucial for the development of carbon materials with high capacitive performance adapted to electrolytes.Phenolic resin based microporous carbon materials with narrow pore size distribution and tunable pore size are prepared by direct pyrolysis of alkoxy groups substituted phenolic resins.The supercapacitive performance of the prepared carbons were studied in KOH electrolytes.The micropore size of the prepared carbons could be controlled with high accuracy by taking advantage of different steric effect of alkoxy groups,respectively.The pore size of prepared carbon are 0.52,0.54,0.58 nm for C2,C6,and C7 sample,respectively.The specific capacitance of C2,C6 and C7 are 42.4 F g^-1,47.4 F g^-1 and 66.12 F g^-1,respectively.