|
| The effect of cobalt element on the electrochemical performance of single-crystal LiNi0.75CoxMn0.25−xO2 cathode materials |
|
Received:September 03, 2025
Revised:September 16, 2025
Accepted:September 24, 2025
Published Online:April 30, 2026
|
| View Full Text View/Add Comment Download reader |
| DOI：10.3969/j.issn.1005-7854.2026.02.017 |
| KeyWord:lithium-ion battery;cathode materials;cobalt element;single crystal;cation mixing;low-temperature performance |
|
| 1.BGRIMM Technology Group, Beijing 100160, China;2.Beijing Easpring Material Technology Co. Ltd., Beijing 100160, China |
| Hits: 40 |
| Download times: 4 |
| Abstract: |
| The global cobalt resources are relatively scarce and expensive, making low-cobalt and cobalt-free designs a crucial development trend for NCM cathode materials in lithium-ion batteries. Single-crystal NCM materials have fewer grain boundaries compared to poly-crystal NCM materials and maintain the integrity of individual particles, thereby reducing particle cracking and pulverization during cycling, as well as suppressing structural phase transitions and gas generation issues. The single-crystal LiNi0.75CoxMn0.25?xO2 (x=0、0.03、 0.05、0.10、0.15) cathode materials with different cobalt contents were synthesized by the high-temperature solid-state reactions and the effects of cobalt contents on the structure and electrochemical performance were investigated. The morphology, crystal structure, and electrochemical performance of the LiNi0.75CoxMn0.25?xO2 materials were analyzed by using FESEM, XRD, and coin cell testing. It is found that as the molar ratio of cobalt increased from 0 to 15%, the degree of single crystallization in the cathode material improved, the unit cell volume gradually decreased, and Li+/Ni2+ cation mixing was significantly reduced. The initial discharge capacity was increased from 207.3 mAh·g?1 to 217.4 mAh·g?1 at 0.1 C in a voltage range of 3.0–4.45 V, and the rate capability was significantly improved. The discharge capacity retention was increased from 90.5% to 95.7%, and from 90.2% to 93.7% after 80 cycles at 25 and 45 ℃, respectively. Additionally, the DCR growth rate before and after cycling was significantly reduced. The discharge capacity retention at ?20 ℃ testing was increased from 74.4% to 82.7%, and the initial DCR at low temperature was decreased, indicating that cobalt plays a positive role in enhancing the low-temperature performance of the material. |
| Close |
|
|
|