Low-valence titanium oxides synthesized by electric field control as novel conversion anodes for high performance sodium-ion batteries
| Autor: | Kangli Wang, Yun Tang, Kai Jiang, Hongwei Tao, Jianwei Hu, Haomiao Li, Min Zhou, Pingyuan Feng, Chen Manlin, Ruxing Wang |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment chemistry.chemical_element 02 engineering and technology General Chemistry Electrolyte 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Cathode 0104 chemical sciences law.invention Anode Chemical engineering chemistry law Electrode General Materials Science Bond energy 0210 nano-technology Stoichiometry Titanium |
| Zdroj: | Journal of Materials Chemistry A. 9:10458-10465 |
| ISSN: | 2050-7496 2050-7488 |
| DOI: | 10.1039/d0ta12552k |
| Popis: | A series of low-valence titanium oxides (TiO and Ti2O) were fabricated by the electric field control approach and their stoichiometric ratios were precisely regulated by adjusting the electrolytic voltage and time. The Na-storage behaviours of the low-valence titanium oxides were investigated for the first time. Compared to conventional TiO2, low-valence titanium oxides undergo conversion reactions with excellent electrochemical performances. The Ti2O electrode delivers a high reversible capacity of 515 mA h g−1, outstanding rate capability of 173 mA h g−1 at 20 A g−1 and superior long-term cycling stability over 1800 cycles. Ex situ characterization reveals the reversible transformation of Ti2O to Ti and Na2O during repeated cycling. Density functional theory (DFT) calculations confirm that the low Ti–O bond energy is in favor of the fracture and recombination of Ti–O bonds, resulting in high capacity through multi-electron conversion reactions. The high conductivity of low-valence titanium oxides is conducive to the rapid transfer of electrons, achieving high electrochemical utilization. In addition, the porous nanostructure generated in situ by chemical conversion reactions could improve Na+ diffusion kinetics and buffer volume changes during sodiation/desodiation processes, thus realizing superior cycling stability and ultrafast charge/discharge ability. Moreover, a full cell coupled with a carbon-coated Na3V2(PO4)3 (Na3V2(PO4)3/C) cathode was assembled, which exhibited a high reversible capacity of 258.4 mA h g−1 and extraordinary cycling performance of 86.5% capacity retention over 100 cycles, demonstrating the potential of low-valence titanium oxides in sodium ion batteries. |
| Databáze: | OpenAIRE |
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