Dimesso, Lucangelo and Becker, Dirk and Spanheimer, Christina and Jaegermann, Wolfram (2014):
Effect of Ca,Mg-ions on the properties of LiCo0.9M0.1PO4/graphitic carbon composites.
In: Progress in Solid State Chemistry, Elsevier Science Publishing, pp. 184-190, 42, (4), ISSN 00796786, [Online-Edition: http://dx.doi.org/10.1016/j.progsolidstchem.2014.04.011],
[Article]
Abstract
LiCo0.9M0.1PO4 (M = Co2+, Mg2+, Ca2+)/graphitic carbon composites are synthesized by Pechini-assisted sol–gel process and annealed by the 2-steps annealing process (300 °C for 5 min in air, then at 730 °C for 12 h in nitrogen). The structural investigation, performed on powders, reveals the presence of LiCoPO4 as the major crystalline phase and of CoP2O7 (M = Co), of Co2P (M = Mg), of Co2P, Li3PO4, (Ca,Co)3(PO4)2 (M = Ca) as impurities. The morphological investigation of the composites shows the formation of crystalline “islands-like” structures with acicular crystallites with different dimensions (typically 5–50 μm) on the top of them. The voltammetric analysis shows a very good reversibility of the (de)intercalation processes and the presence of two mean peak maxima in the cathodic region at ∼5.01 V and ∼5.05 V respectively. The discharge specific capacities, at a discharge rate of C/10 and room temperature, were 100 mAh g−1 for M = Co, 68 mAh g−1 for M = Mg and 104 mAh g−1 for M = Ca respectively. The electrochemical impedance spectroscopy data reveal a decrease of the electrical resistance and the improvement of the Li-ion conductivity in the Ca and Mg ions containing composites.
| Item Type: | Article |
|---|---|
| Erschienen: | 2014 |
| Creators: | Dimesso, Lucangelo and Becker, Dirk and Spanheimer, Christina and Jaegermann, Wolfram |
| Title: | Effect of Ca,Mg-ions on the properties of LiCo0.9M0.1PO4/graphitic carbon composites |
| Language: | English |
| Abstract: | LiCo0.9M0.1PO4 (M = Co2+, Mg2+, Ca2+)/graphitic carbon composites are synthesized by Pechini-assisted sol–gel process and annealed by the 2-steps annealing process (300 °C for 5 min in air, then at 730 °C for 12 h in nitrogen). The structural investigation, performed on powders, reveals the presence of LiCoPO4 as the major crystalline phase and of CoP2O7 (M = Co), of Co2P (M = Mg), of Co2P, Li3PO4, (Ca,Co)3(PO4)2 (M = Ca) as impurities. The morphological investigation of the composites shows the formation of crystalline “islands-like” structures with acicular crystallites with different dimensions (typically 5–50 μm) on the top of them. The voltammetric analysis shows a very good reversibility of the (de)intercalation processes and the presence of two mean peak maxima in the cathodic region at ∼5.01 V and ∼5.05 V respectively. The discharge specific capacities, at a discharge rate of C/10 and room temperature, were 100 mAh g−1 for M = Co, 68 mAh g−1 for M = Mg and 104 mAh g−1 for M = Ca respectively. The electrochemical impedance spectroscopy data reveal a decrease of the electrical resistance and the improvement of the Li-ion conductivity in the Ca and Mg ions containing composites. |
| Journal or Publication Title: | Progress in Solid State Chemistry |
| Volume: | 42 |
| Number: | 4 |
| Publisher: | Elsevier Science Publishing |
| Uncontrolled Keywords: | Composites, Cathode material, Lithium cobalt phosphate, Isovalent substitution, Calcium, Magnesium |
| Divisions: | 11 Department of Materials and Earth Sciences > Material Science > Surface Science 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences |
| Date Deposited: | 27 Feb 2015 12:14 |
| Official URL: | http://dx.doi.org/10.1016/j.progsolidstchem.2014.04.011 |
| Identification Number: | doi:10.1016/j.progsolidstchem.2014.04.011 |
| Funders: | The authors thank the Deutsche Forschungsgemeinschaft(DFG) (Sonderinitiativeproject: PAK-177, grant number. JA859/14-3) for the financial support during this work. , The DFG encourage and financially support the publication of the results during the projects. |
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