| YU Kai,WANG Shouren,WANG Yingzi.Surface Texturing Design and Surface Wettability Study of LiFePO4 Electrode[J],54(4):180-190 |
| Surface Texturing Design and Surface Wettability Study of LiFePO4 Electrode |
| Received:September 03, 2024 Revised:November 06, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.04.014 |
| KeyWord:surface texture lithium-ion battery wettability LiFePO4 ultrafast pulsed laser etching topography contact angle |
| Author | Institution |
| YU Kai |
School of Mechanical Engineering,School of Materials Science and Engineering, University of Jinan, Jinan , China |
| WANG Shouren |
School of Mechanical Engineering,School of Materials Science and Engineering, University of Jinan, Jinan , China |
| WANG Yingzi |
School of Mechanical Engineering,School of Materials Science and Engineering, University of Jinan, Jinan , China |
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| Abstract: |
| Lithium-ion batteries are widely used due to their excellent performance. As a commonly used electrode material for lithium-ion batteries, LiFePO4 has many advantages such as low cost, high safety and high stability. However, the one-dimensional channel of the olivine structure greatly limits the discharge performance of lithium-ion batteries. In addition, the discharge process of lithium-ion batteres is based on the interface interaction between the electrode and electrolyte, and the wettability directly determines the battery performance. Laser texturing is a method to improve the wettability and discharge performance of lithium-ion batteries, with the advantages of small damage and non-contact. This technology has been partially applied to the battery production process. In this study, micro-grooves were prepared on the surface of the LiFePO4 electrode by ultra-fast pulsed laser technique. The influences of micro-texture on the electrode surface morphology and chemical composition were systematically studied by means of scanning electron microscope, X-ray photoelectron spectroscopy, non-contact three-dimensional optical profilometer. The effect of micro-texture on the wettability of the electrode surface was evaluated quantitatively and qualitatively by contact angle measuring instrument and simulation, respectively. In addition, a battery test system and a potentiostat were used to comprehensively evaluate the discharge performance and diffusion kinetics of lithium-ion batteries. The results showed that the wettability of the electrode surface was significantly improved by micro-texture. It was found that the contact angle of electrolyte on the textured electrode surface was inversely related to the texture aspect ratio, which was reduced to 7.1° at most. Furthermore, it was observed from the optical microscope that the diffusion area of the structured electrode surface increased to 26.52 mm2 and the wetting time shortened to 6 s. At the same time, the electrolyte spread radially and symmetrically on the original electrode surface, while the wetting process of the textured electrode surface showed anisotropy. The simulation results showed that the electrolyte was in the Wenzel wetting state, and the fitting contact angle equation could better explain the change trend of the contact angle. In addition, the content of oxygen-containing groups on the structured electrode increased significantly compared with the original electrode, consistent with the change trend of the contact angle. This result showed that laser ablation increased the surface energy of the electrode, and C==O was the key factor to improve the hydrophilicity of the electrode surface. The original electrode had the worst surface wettability, and the electrode material in the dry part promoted the cell decay, thus showing the worst discharge performance. Although laser texturing resulted in loss of electrode capacity, it promoted further wetting of the electrode and allowed more of the deeper material to simultaneously participate in the battery reaction. Compared with the original electrode, the discharge performance of the structured electrodes was significantly improved, the capacity retention rate at 0.5 C was increased from 58.4% to 99.4%, and the maximum lithium-ion diffusion coefficient (2.67×10−13 cm2/s) was displayed. This indicates that the further wetting of electrode material improves the diffusion dynamics of lithium ions and improves the discharge performance of lithium-ion batteries. It provides some guidance for the preparation of high-performance lithium-ion batteries. |
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