Alginic acid aquagel as a template and carbon source in the synthesis of Li4Ti5O12/C nanocomposites for application as anodes in Li-ion batteries

Role of gelatin and chitosan cross-linked aqueous template in controlling the size of lithium titanium oxide

Significant safety advantages of lithium titanium oxide (LTO) over currently used graphite for lithium-ion batteries have been attracting scientists to develop novel synthetic methods of this anode material in order to combine with another cathode. This study utilizes self-sacrificing cross-linked aqueous templates of gelatin and chitosan polymer to control lithium titanium oxide (LTO) morphology and microstructure. Gelatin and chitosan self-assembled aqueous template containing LTO precursors has been evaporated at 110 °C and then calcined at 750 °C in a muffle furnace to synthesize white color LTO powder. Various techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and UV–visible spectroscopy were used to characterize the synthesized LTO powders. Both XRD and EDS spectrum confirm the coating of gelatin and chitosan derived carbon species on the surface of LTO materials. The detailed characterization reveals that increasing the amount of gelatin to the mass ratio of gelatin and chitosan reduced LTO particle sizes. Thus, a size controlled carbon coating LTO preparation strategy have been established via gelatin and chitosan cross-linked aqueous template in controlling the morphology and microstructure of LTO material.

Dehydration of Alginic Acid Cryogel by TiCl4 vapor: Direct Access to Mesoporous TiO2 @C Nanocomposites and Their Performance in Lithium-Ion Batteries

A new strategy for the synthesis of mesoporous TiO₂ @C nanocomposites through the direct mineralization of seaweed-derived alginic acid cryogel by TiCl₄ through a solid/vapor reaction pathway is presented. In this synthesis, alginic acid cryogel can have multiple roles; i) mesoporous template, ii) carbon source, and iii) oxygen source for the TiO₂ precursor, TiCl₄ . The resulting TiO₂ @alginic acid composite was transformed either into pure mesoporous TiO₂ by calcination or into mesoporous TiO₂ @C nanocomposites by pyrolysis. By comparing with a nonporous TiO₂ @C composite, the importance of the mesopores on the performance of electrodes for lithium-ion batteries based on mesoporous TiO₂ @C composite was clearly evidenced. In addition, the carbon matrix in the mesoporous TiO₂ @C nanocomposite also showed electrochemical activity versus lithium ions, providing twice the capacity of pure mesoporous TiO₂ or alginic acid-derived mesoporous carbon (A600). Given the simplicity and environmental friendliness of the process, the mesoporous TiO₂ @C nanocomposite could satisfy the main prerequisites of green and sustainable chemistry while showing improved electrochemical performance as a negative electrode for lithium-ion batteries.