王京博,曹利,李松原,肖荣诗,黄婷.Cu箔集流体飞秒激光深刻蚀织构化及其对锂离子电池性能的影响[J].表面技术,2024,53(1):115-122.
WANG Jingbo,CAO Li,LI Songyuan,XIAO Rongshi,HUANG Ting.Texturing of Cu Foil Current Collector by Femtosecond Laser Deep Ablation and Its Effect on Performance of Lithium-ion Batteries[J].Surface Technology,2024,53(1):115-122 |
| Cu箔集流体飞秒激光深刻蚀织构化及其对锂离子电池性能的影响 |
| Texturing of Cu Foil Current Collector by Femtosecond Laser Deep Ablation and Its Effect on Performance of Lithium-ion Batteries |
| 投稿时间：2022-11-24 修订日期：2023-05-05 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.01.011 |
| 中文关键词: 绿光飞秒激光 激光刻蚀 Cu箔集流体 Si电极 循环稳定性 |
| 英文关键词:green femtosecond laser laser ablation Cu foil current collector Si-based electrode cycling stability |
| 基金项目:国家自然科学基金(51975018) |
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| Author | Institution |
| WANG Jingbo | Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China |
| CAO Li | Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China |
| LI Songyuan | Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China |
| XIAO Rongshi | Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China |
| HUANG Ting | Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China |
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| 中文摘要: |
| 目的 使用飞秒激光在Cu箔表面深刻蚀织构化，制备微纳沟槽结构，提高锂离子电池Si电极循环稳定性。方法 系统研究激光能量密度、单位点有效脉冲数对厚度为9 μm的Cu箔的表面形貌和微纳结构的影响规律，根据结果设计不同沟槽密度和沟槽深度的Cu箔，并组装成Si电极锂离子半电池，通过循环测试及循环后电极形貌揭示其稳定性提升的内在机理。结果 最佳的激光能量密度为3.18 J/cm2，此时改变单位点有效脉冲数和扫描间距可有效控制刻蚀沟槽的密度和深度。Si电极的循环稳定性随着Cu箔表面沟槽密度和沟槽深度的增加而逐渐提升，当沟槽密度为75%、沟槽深度为6 μm时，循环300圈后剩余的容量高达911 mA.h/g，保持率为89%，电极形貌相对最完整、稳定。结论 刻蚀表面纳米结构增加了电极层与集流体之间的黏结强度;微米沟槽结构进一步保护了电极层，缓解了体积膨胀效应。采用Cu箔集流体深刻蚀显著改善了Si电极的剥离和开裂现象，实现了其电化学性能的提升。 |
| 英文摘要: |
| The significant volume expansion of Si-based electrodes is very likely to lead to electrode materials exfoliation at the interface of Cu foil current collectors, and the interfacial stability of the electrode is a critical issue to be addressed urgently. Femtosecond laser ablating is an advanced surface processing technology, which can produce micro-nano surface structures with regular patterns and significantly improve the adhesive strength. In this paper, a green femtosecond laser with a wavelength of 515 nm was employed to deeply ablate and texture the Cu foils (9 μm-thick), and the effects of laser energy density and effective pulse number on the surface morphology and micro-nano structure of Cu foil as well as the cycle stability of Si-based electrodes of Cu foil samples with different structures were investigated. A femtosecond laser (TruMicro 5280 Femto Edition, TRUMPF) equipped with a scanning galvanometer (Scanlab Hurry SCAN14) was employed to deeply ablate the groove structure on the Cu foil surface. The univariate method was adopted. Firstly, the effective pulse number was fixed at 5, and the laser energy density was 1.27, 1.91, 2.55, 3.18, 3.82, 6.37 J/cm2, respectively. Then the laser energy density was fixed at 3.18 J/cm2, and the effective pulse number was 5, 25, 50, 75, respectively. Based on the results, Cu foils with different groove densities and groove depths were designed. The surface morphology of Cu foil was observed with a scanning electron microscope (HITACHI S-3400N) and a super-depth-of-field microscope (KEYENCE VHX-950F). The elemental content of the Cu foil surface was characterized with an energy spectrometer. The active material layer was formulated and coated on the surface of the Cu foil current collector. The active material layer was composed of 70% of active material Si (100 nm in diameter), 20% of binder and 10% of conductive agent. The electrodes (active layers and current collectors) were dried for 8 h at 80 ℃ under vacuum before they were transferred into the glove box for cell assembly. The cells were tested by galvanostatic cycling at 1C rate. It was found that the ablation threshold of the green femtosecond laser of Cu foil was 0.52 J/cm2, and the width of the ablated area increased gradually with the laser energy density. But when the laser energy density was too high, the ablating effect appeared "saturation" phenomenon. The surface of the ablated groove was nanostructured and no significant oxidation occurred. The optimal laser energy density for deeply etching was 3.18 J/cm2, and the depth of the groove could be regulated by changing the effective pulses number. The cycle stability of the Si-based electrodes gradually increased with the increase of groove density and depth. It was worth noting that when the groove density was 75% and the groove depth was 6 μm, the capacity remained 911 mA.h/g after 300 cycles at 1C with a retention rate of 89%. Using femtosecond laser deep ablation method and optimizing the laser parameters can successfully prepare micron-groove structure on the surface of Cu foil. The nanostructure increases the adhesive strength between the electrode and the current collector, while the micro-groove structure protects the electrode and alleviates its volume expansion. The deeply ablated Cu foil significantly improves the exfoliation of the Si-based electrodes and achieves the enhancement of the electrochemical performance. |
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