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| Effect of Mg and Na Co-doping on Structure and Electrochemical Performance of Li-rich Cathode Materials |
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Received:November 04, 2020
Revised:November 12, 2020
Accepted:November 16, 2020
Published Online:March 24, 2021
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| DOI：doi：10.3969/j.issn.1007-7545.2021.04.014 |
| KeyWord:doping; Li-rich; cathode material; electrochemical performance |
| Author | Institution |
| LI Wei-wei |
新乡学院 化学与材料工程学院 |
| ZHANG Ting |
新乡学院 化学与材料工程学院 |
| LIU hui |
新乡学院 化学与材料工程学院 |
| YAO Lu |
新乡学院 化学与材料工程学院 |
| SI Jiang-ju |
新乡学院 化学与材料工程学院 |
| LI Peng-fa |
新乡学院 化学与材料工程学院 |
| LANG Wu-ke |
新乡学院 化学与材料工程学院 |
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| Abstract: |
| Cobalt free Li-rich manganese based cathode materials with Na and Mg co-doping were prepared by sol-gel method. Morphology, microstructure and electrochemical properties of cobalt free Li-rich manganese based cathode materials were tested by transmission electron microscopy (HRTEM), X ray diffractometer (XRD), X ray photoelectron spectroscopy (XPS), charge discharge tester and electrochemical workstation. The results show that particle size of all samples is about 100 nm with near-spherical. There are no heterophase peaks in samples, all of them have good layered structure, and Na+ and Mg2+ has no effect on oxidation state of Ni and Mn ions. LNi018 has best electrochemical performance with initial discharge capacity of 225.5 mAh/g and coulombic efficiency of 78.0%, and capacity retention rate is 83.1% after 250 cycles. Ni content in LNi018 sample is less than that of other samples, valence states of Ni2+ and Mg2+ are the same, and ionic radius is approximate (Ni2 + 6.9 nm, Mg2+ 7.2 nm), Mg2+ takes place of Ni2+ in lattice. At the same time, the larger radius of Na+ (10.2 nm) rises lithium layer spacing, which makes crystal structure more stable during charge discharge cycle, thus maintaining a higher discharge voltage and capacity. |
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