Study On The Template Synthesis Of Carbon Materials For The Application In Supercapacitor

In recent years, supercapacitors are energy storage devices of the rapid development, and they are between conventional capacitors and rechargeable batteries which have fast charge and discharge of the new type power energy storage devices, and have the broad application prospect. Studies have shown that the electrode material plays a decisive impact on its performance. Among them, the carbon material has excellent characteristics such as good conductivity, large specific surface area, pore structure control, low density, sources in routine, low price and so on. So carbon materials as supercapacitors electrode materials have the high attention of people. This paper uses the template carbonization preparation of porous carbon materials, nanoporous carbon materials are through changing the carbon source type, templates type, carbonization temperature, carbonization time, mass ratio, and mixed nitrogen method in order to achieve large specific surface area, the high entrance, the pore size distribution and regulation of high energy density and high power density, the preparation of the capacitive performance of controlled structure, carbon materials. The main content of the paper is as follows:1. A simple but efficient dual-template carbonization method has been developed to produce nanoporous carbon as high performance supercapacitor electrode material. Sodium carboxymethyl cellulose (NaCMC) acts as carbon source, and inexpensive Mg(OAc)24H2O and Zn(OAc)2-2H2O as dual hard templates. It reveals that the carbonization temperature and the mass ratio of NaCMC, Mg(OAc)2-4H2O and Zn(OAc)2-2H2O are crucial for determining the carbon structure. The NaCMC-Mg-Zn-1:5:0.5 sample displays highly porous structure with large surface area (1596 m2 g-1), pore volume (5.93 cm3 g-1) and hierarchical pore size distribution. The carbon sample is measured in a two/three-electrode system, respectively. It has a high specific capacitance of 428.4 F g-1 at 1 A g-1, together with good rate capability and nice cycling durability. A high energy density up to 68.6 Wh kg-1 can be achieved as the power density of 1.5 kW kg-1. The templates used in this work are cheap, commercially available and this template carbonization method, especially without any activation process, can be readily extended to prepare other kinds of nanoporous carbon.2. We demonstrate a simple template carbonization method to prepare nanoporous carbons, using zinc citrate (Zn3(C6H5O7)2·2H2O) as carbon source as well as template itself. Furthermore, ZnCl2 has been implemented as activation agent to improve the electrochemical performance of carbons. It reveals that the addition of ZnCl2 can greatly influence the carbon structures and the resulting electrochemical performances as supercapacitor electrode materials. The surface areas have increased from 740.5 to 1244.2 m2 g-1, and total pore volume from 1.96 to 2.21 cm3 g-1. The specific capacitances have elevated from 194.8 to 335.6 F g-1 at a current density of 2 A g-1, and the capacitance retentions have improved from 83.7% to 96.5%. This kind of template carbonization method combined with ZnCl2 activation is efficient for producing nanoporous carbons.3. Nanoporous carbon materials were produced by using dithizone (C6H5NHNHCSN=NC6H5) and diphenyl azo carbon hydrazide (C13H12N4O), and their electrochemical behaviors had been investigated. (1) Dithizone and magnesium powder with different mass ratio were carbonized at 800℃ to produce nanoporous carbon under Ar flow, as well as using dithizone and zinc powder. Electrochemical behaviors of the obtained nanoporous carbon materials were measured and compared through cyclic voltammetry and galvanostatic charge/discharge. It turned out that nanoporous carbon derived from dithizone and magnesium powder with the mass ratio of 1:1 exhibits the best electrochemical performance. It had a specific capacitance of 229.3 F g-1 at the current density of 1 A g-1,and still maintain at 74.8 F g-1 even at 40 A g-1(2) Dithizone and magnesium nitrate with different mass ratio were carbonized to produce nanoporous carbon under Ar flow, as well as using diphenyl azo carbon hydrazide and magnesium nitrate. Electrochemical behaviors of the obtained nanoporous carbon materials were measured and compared through cyclic voltammetry and galvanostatic charge/discharge. It turned out that nanoporous carbon derived from dithizone and magnesium nitrate with the mass ratio of 1:3 exhibits the best electrochemical performance. The obtained carbon shows a specific capacitance of 268.5 F g-1 at 1 A g-1, and a capacitance retention of 54.38% in the case of 146.0 F g-1 at 20 A g-1.