| With the rapid improvements of modern sciences and technologies,the requirement of energy increases year by year.The amount of traditional fossil resource is limited,and the pollution followed with the consumption of fossil energy is extremely severe.Because of these,it is our necessary to search the next generation energy storage devices.Lithium ion battery(LIB)has attracted much interests owning to its distinguishes.But,the limitation and high cost of the lithium source have restricted the widely applications of LIB.Sodium is not only similar with lithium,but also much cheaper than lithium.LIB and SIB both have a promising future due to their own performances under the background of rapid development of technology.As one of porous carbons,ordered mesoporous carbon(OMC)has attracted much interests in energy storage devices because of the good properties,stable physical and chemical performance,high specific surface area and ordered mesoporous pore structure.In this work,OMCs with various structures have been prepared through one-step carbonization of triblock copolymer/silica/alcohols composites to correlated the relationship between the structure and electrochemical performance.In the last,we improve the ability of energy storage by modifying the carbon or preparing the composites.The main contents of the whole paper are shown below:(1)Rod-like OMCs with various structures are synthesized in triblock copolymer P123/silica/glycerol system by changing the concentration of hydrochloric acid.The electrochemical results show that OMC with larger pore size and shorter pore channel presents a higher capacity and better rate performance when used as the anodes for SIB.(2)OMC is prepared in triblock copolymer P123/silica/butanol system at the presence of sulfuric acid.It is appropriate for forming the spherical structure when the volume of butanol addition is 2.5 ml,and the temperature of carbonization is 800 ?.The specific surface area of this spherical material is 1170.7 m2/g,while the pore sizes are 3.3 and 9.7 nm.The spherical carbon shows a higher capacity of 76.4 mA h g-1 at current density of 5 A g-1 owning to the ordered pore structure,facilitating the diffusion of electrolyte and transportation of ion.(3)Nitrogen is brought into OMC through ammonia activation without destroying the spherical morphology or the ordered pore channel.The content of nitrogen is controllable from 0.04 to 2.83 wt%by changing the temperature.The carbon shows a better performance when the temperature of ammonia activation is 900 ?.The specific capacity of the nitrogen-doped carbon material is 1069.4 mA h g-1 at 50 mA g-1,and the reversible specific capacity of the nitrogen-doped carbon material is around 170.8 mA h g-1 at 5 A g-1 after 500 cycles with the coulombic efficiency approximately of 100%.(4)Fe3O4/OMC is prepared through wet-impregnation easily,while the content of Fe3O4 is 41.20 wt%.Fe3O4/OMC composites still keep the ordered structure.The cycle performance of Fe3O4/OMC is better than the OMC when used as anodes for LIB.The specific capacity of Fe3O4/OMC is 578.3 mA h g-1,while the specific capacity of OMC is 543 mA h g-1?... |
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