Protective Spinel Coating for Li<sub>1.17</sub>Ni<sub>0.17</sub>Mn<sub>0.50</sub>Co<sub>0.17</sub>O<sub>2</sub> Cathode for Li-Ion Batteries through Single-Source Precursor Approach
oleh: Andrey Shevtsov, Haixiang Han, Anatolii Morozov, Jesse C. Carozza, Aleksandra A. Savina, Iaroslava Shakhova, Nellie R. Khasanova, Evgeny V. Antipov, Evgeny V. Dikarev, Artem M. Abakumov
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2020-09-01 |
Deskripsi
The Li<sub>1.17</sub>Ni<sub>0.17</sub>Mn<sub>0.50</sub>Co<sub>0.17</sub>O<sub>2</sub> Li-rich NMC positive electrode (cathode) for lithium-ion batteries has been coated with nanocrystals of the LiMn<sub>1.5</sub>Co<sub>0.5</sub>O<sub>4</sub> high-voltage spinel cathode material. The coating was applied through a single-source precursor approach by a deposition of the molecular precursor LiMn<sub>1.5</sub>Co<sub>0.5</sub>(thd)<sub>5</sub> (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) dissolved in diethyl ether, followed by thermal decomposition at 400 °C inair resulting in a chemically homogeneous cubic spinel. The structure and chemical composition of the coatings, deposited on the model SiO<sub>2</sub> spheres and Li-rich NMC crystallites, were analyzed using powder X-ray diffraction, electron diffraction, high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X-ray (EDX) mapping. The coated material containing 12 wt.% of spinel demonstrates a significantly improved first cycle Coulombic efficiency of 92% with a high first cycle discharge capacity of 290 mAhg<sup>−1</sup>. The coating also improves the capacity and voltage retention monitored over 25 galvanostatic charge–discharge cycles, although a complete suppression of the capacity and voltage fade is not achieved.