High-pressure synthesis and electrochemical properties of lithium transition metal oxides with layered rock-salt structure
| Autor: | Hansen Chang, Ryoji Kanno, Genki Kobayashi, Masaaki Hirayama, Kei Kubota |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment Rietveld refinement Inorganic chemistry Analytical chemistry Energy Engineering and Power Technology chemistry.chemical_element Electrochemistry Lithium-ion battery chemistry Transition metal Phase (matter) Lithium Electrical and Electronic Engineering Physical and Theoretical Chemistry Inductively coupled plasma Spectroscopy |
| Zdroj: | Journal of Power Sources. 252:1-7 |
| ISSN: | 0378-7753 |
| DOI: | 10.1016/j.jpowsour.2013.11.050 |
| Popis: | Li-rich layered transition metal oxides with the nominal composition of Li 1+ x [Li 0.2 Mn α Co β Ni γ ]O 2 with 0.0 ≤ x ≤ 0.7 are synthesized using a high-pressure technique. The chemical compositions are determined using inductively coupled plasma (ICP) spectroscopy and the structure is identified from X-ray diffraction measurements as a mixture of rhombohedral R -3 m and cubic Fm -3 m phases. Rietveld refinement analysis reveals that the layered to cubic phase ratio increases as x tends towards 0.7, with an almost complete cubic phase present for x ≥ 0.6. Electrochemical charge–discharge experiments performed using coin cells and show capacities of around 200 mAh g −1 for 0.0 ≤ x ≤ 0.4 samples, although the capacity quickly decreases for x ≥ 0.5, which is consistent with the trend towards a predominantly cubic phase. The plateau for oxygen generation, which appears at the 4.4 V threshold, is reduced as x increases. |
| Databáze: | OpenAIRE |
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