The microstructure and performance of Li4Ti5O12 doped by Mg prepared by hydrothermal method and solid phase method were investigated. Lithium dihydrate, magnesium acetate and tetrabutyl titanate were used as the main ...The microstructure and performance of Li4Ti5O12 doped by Mg prepared by hydrothermal method and solid phase method were investigated. Lithium dihydrate, magnesium acetate and tetrabutyl titanate were used as the main raw materials. This study reveals that Mg^2+ has influences on the spherical structure, crystal development of Li4Ti5O12 and the electrochemical performances. The hollow spherical structure is composed of nano-sheet structure and the nano-sheet structure can be affected by the Mg^2+ content. For Li4-xMgxTi5 O12, the sheet structure can be refined with the increment of Mg^2+ content when x value is 0-0.1 and coarsen with the increment of Mg^2+ content when x value is 0.1-0.2. The hollow spherical Li4Ti5O12 powders prepared by hydrothermal method have better performance. The optimal Mgdoped amount of hydrothermal method is 0.1. At 0.1 C, the first discharge capacity of Li3.9Mg0.1Ti5O12 prepared through hydrothermal method at 0.1 C and 10 cycles is 182 and 178 mA hg^-1, respectively.展开更多
In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other adde...In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion.It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion,while adding PEI into suspen-sions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement.Therefore,the latter was chosen as the method in dispersing HSNP suspensions.The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated.The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles,hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions.The change of HSNP’s ■ potential after adding PEI and the rela-tionship between the adsorbed amount of PEI and pH were also investigated.展开更多
基金Funded by the National Natural Science Foundation of China(No.51072162).
文摘The microstructure and performance of Li4Ti5O12 doped by Mg prepared by hydrothermal method and solid phase method were investigated. Lithium dihydrate, magnesium acetate and tetrabutyl titanate were used as the main raw materials. This study reveals that Mg^2+ has influences on the spherical structure, crystal development of Li4Ti5O12 and the electrochemical performances. The hollow spherical structure is composed of nano-sheet structure and the nano-sheet structure can be affected by the Mg^2+ content. For Li4-xMgxTi5 O12, the sheet structure can be refined with the increment of Mg^2+ content when x value is 0-0.1 and coarsen with the increment of Mg^2+ content when x value is 0.1-0.2. The hollow spherical Li4Ti5O12 powders prepared by hydrothermal method have better performance. The optimal Mgdoped amount of hydrothermal method is 0.1. At 0.1 C, the first discharge capacity of Li3.9Mg0.1Ti5O12 prepared through hydrothermal method at 0.1 C and 10 cycles is 182 and 178 mA hg^-1, respectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.20506001 and 20236020)the Program for New Century Excellent Talents in University(Grant No.NCET-04-0123)Beijing Municipal Commission of Education(Grant No.JD100100403).
文摘In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion.It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion,while adding PEI into suspen-sions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement.Therefore,the latter was chosen as the method in dispersing HSNP suspensions.The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated.The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles,hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions.The change of HSNP’s ■ potential after adding PEI and the rela-tionship between the adsorbed amount of PEI and pH were also investigated.
