掺N多孔炭/NiO的制备与电容性能的研究
Synthesis and capacitance properties of N-doped porous carbon / NiO composite materials
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摘要: 以原位聚合法制备的煤基聚苯胺为碳、氮源,乙酸镍为催化剂前驱体,催化热解制得掺N多孔炭/Ni,再经液相氧化,成功制得掺N量为0.256%,有丰富微介孔的掺N多孔炭/NiO。其孔结构以小于40 nm的微介孔为主,微孔孔体积占80.4%,BET比表面积为452.5 m2/g,BET平均孔径为1.9 nm,BJH平均孔径为3.5 nm。其中,多孔炭保留了部分煤大分子的芳核特征,表面还有一定量的羧基和羟基,N元素主要以吡啶型N和吡咯型的形式掺杂到多孔炭中。NiO以100 nm左右的微粒附着在多孔炭表面或孔中。制备的掺N多孔炭/NiO兼具双电层电容和赝电容特性,具有高的比电容,好的循环稳定性和倍率特性。其单极比电容达到541.6 F/g(1.0 A/g),5.0 A/g下循环充放电1 000次后,比电容降为245.8 F/g,电容保持率为85.6%。Abstract: N-doped porous carbon / Ni is synthesized through pyrolysis,using coal-based polyaniline prepared by an in- situ polymerization approach as the carbon and nitrogen source,nickel acetate as the catalyst precursor. Next it is suc- cessfully transformed to N-doped porous carbon / NiO through a liquid-phase oxidation,which contains 0. 256% nitro- gen content and rich micro-mesopores. Its pore size is less than 40 nm,the microporous volume is 80. 4% ,the BET specific surface area is 452. 5 m2 / g,the BET average pore width is 1. 9 nm,and the BJH adsorption average pore di- ameter is 3. 5 nm. Among them,the porous carbon retains the aromatic nucleus of some coal macromolecules,its sur- face also has a certain amount of carboxyl and hydroxyl groups,and nitrogen element is mainly doped into the porous carbon in the form of pyridinic N and pyrrolic N. NiO particles about 100 nm diameter are embedded on the surface or in the pores of porous carbon. The as-synthesized N-doped porous carbon / NiO combines the electric double-layer ca- pacitance capacity of porous carbon and pesudocapacitance capacity of NiO. It has a high specific capacitance,good cycling stability and rate performance. Its specific capacitance is high to 541. 6 F / g at the current density of 1. 0 A / g. And it is reduced to 245. 8 F / g at 5. 0 A / g for 1 000-cycle charge-discharge tests and the capacitance retention is up to 85. 6% .