Reversible Sodium Storage of CoTe<sub>2</sub> Anode via Lanthanum Doping
Cobalt telluride (CoTe<sub>2</sub>) is considered an advanced anode material for sodium-ion batteries (SIBs) because of its high theoretical capacity and high conductivity. Nevertheless, the ionic radius of the Co<sup>2+</sup> ion (0.74 Å) is smaller than that of the Na<su...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Inorganics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-6740/13/6/207 |
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| Summary: | Cobalt telluride (CoTe<sub>2</sub>) is considered an advanced anode material for sodium-ion batteries (SIBs) because of its high theoretical capacity and high conductivity. Nevertheless, the ionic radius of the Co<sup>2+</sup> ion (0.74 Å) is smaller than that of the Na<sup>+</sup> ion, meaning the integrity of CoTe<sub>2</sub> electrodes can be easily damaged when Na<sup>+</sup> ions diffuse into CoTe<sub>2</sub> and convert to large Na<sub>2</sub>Te. Herein, we propose a doping strategy by introducing an unreactive element but with a large radius to enhance the overall performance. Lanthanum (La) can be doped into the CoTe<sub>2</sub> structure to counteract the size effect of Na<sub>2</sub>Te since La has a large radius. On the other hand, La with abundant electrons in CoTe<sub>2</sub> can also facilitate the charge transfer during charge/discharge. As a result, La-doped CoTe<sub>2</sub> (La-CoTe<sub>2</sub>) can deliver a maximum capacity of 345 mAh g<sup>−1</sup> at 0.05 A g<sup>−1</sup> and has a decent rate performance. After 2000 cycles at 2 A g<sup>−1</sup>, a capacity of 88 mAh g<sup>−1</sup> remained, which is a notable improvement compared to undoped CoTe<sub>2</sub>. These results demonstrate the potential of rare earth elements in preparing advanced SIB electrode materials. |
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| ISSN: | 2304-6740 |