Facile one-pot synthesis of Ge/TiO2 nanocomposite structures with improved electrochemical performance
| Autor: | Kyung-Won Park, Sojeong Choi, Sang-Hyun Moon, Hyeona Kim, Min-Cheol Kim, Yo-Seob Kim |
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| Rok vydání: | 2019 |
| Předmět: |
Nanocomposite
Materials science chemistry.chemical_element Germanium 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Amorphous solid chemistry.chemical_compound chemistry X-ray photoelectron spectroscopy Chemical engineering Electrode General Materials Science Graphite Titanium isopropoxide 0210 nano-technology Faraday efficiency |
| Zdroj: | Nanoscale. 11:17415-17424 |
| ISSN: | 2040-3372 2040-3364 |
| DOI: | 10.1039/c9nr04315b |
| Popis: | Germanium (Ge) as an alternative to graphite exhibits a fairly high theoretical energy density and improved Li+ ion diffusivity. However, the seriously deteriorated electrochemical performance of Ge during cycling and the difficulty in the preparation of Ge-based nanostructures can hinder the utilization of Ge as an anode. Thus, in this study, a nanocomposite structure with Ge and TiO2 (Ge/TiO2) was synthesized using a facile one-pot method with different ratios of a Ge source with a dominant GeO2 phase and titanium isopropoxide. From X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy, the Ge/TiO2 nanocomposites were found to be spherical structures homogeneously consisting of the reduced Ge as an active material and amorphous TiO2 as a matrix. In particular, the Ge/TiO2 nanocomposite with an appropriate amount of TiO2 exhibited improved electrochemical properties, i.e., a coulombic efficiency of 97% and a retention of 61% for 100 cycles, compared to commercial Ge (a coulombic efficiency of 82% and a retention of 16%). This demonstrates that the amorphous TiO2 matrix could relieve a volumetric expansion of the Ge active material in the nanocomposite electrode generated during the cycling process. |
| Databáze: | OpenAIRE |
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