Si是非常有前途的阳极材料,因为其优异的理论容量高达3579mAh/g。然而,值得注意的是,Si阳极在充电和放电期间经历显著的体积膨胀(>300%)。由于阳极涂层和光滑的Cu箔集流体之间的附着力弱,体积膨胀的硅阳极容易脱落,从而破坏阳极循环性能。在本研究中,波长为515nm的飞秒激光用于纹理具有分层微观结构和纳米结构的Cu箔。成功地减少了Si阳极中的剥离和开裂现象,证明成交量扩张得到了有效缓解,这归因于纳米结构的高比表面积和深烧蚀微槽的保护。此外,分层结构降低界面电阻以促进电子转移。Si阳极实现了改进的循环稳定性和倍率能力,并研究了结构特征对上述性能的影响。凹槽密度为75%、深度为15μm的20μm厚Cu集流器上的Si阳极在1C下300次循环后表现出1182mAh/g的容量,并在3℃下表现出684mAh/g的高速率容量。
Si is a highly promising anode material due to its superior theoretical capacity of up to 3579 mAh/g. However, it is worth noting that Si anodes experience significant volume expansion (>300%) during charging and discharging. Due to the weak adhesion between the anode coating and the smooth Cu foil current collector, the volume-expanded Si anode easily peels off, thus damaging anode cycling performance. In the present study, a femtosecond laser with a wavelength of 515 nm is used to texture Cu foils with a hierarchical microstructure and nanostructure. The peeling and cracking phenomenon in the Si anode are successfully reduced, demonstrating that volume expansion is effectively mitigated, which is attributed to the high specific surface area of the nanostructure and the protection of the deep-ablated microgrooves. Moreover, the hierarchical structure reduces interfacial resistance to promote electron transfer. The Si anode achieves improved cycling stability and rate capability, and the influence of structural features on the aforementioned performance is studied. The Si anode on the 20 μm-thick Cu current collector with a groove density of 75% and a depth of 15 μm exhibits a capacity of 1182 mAh/g after 300 cycles at 1 C and shows a high-rate capacity of 684 mAh/g at 3 C.