Improving cycle stability of Si anode through partially carbonized polydopamine coating
Improving cycle stability of Si anode through partially carbonized polydopamine coating
复制标题
DOI：
10.1016/j.jelechem.2020.114738
复制
发表时间：
2020-11-01
影响因子：
4.5
通讯作者：
Shaw, Leon L.
中科院分区：
文献类型：
--
作者：
Ashuri, Maziar;He, Qianran;Shaw, Leon L.
在这项研究中，我们报告了第一次调查的有效性的部分转化的碳涂层从聚多巴胺（PODA），以提高循环稳定性的Si阳极的锂离子电池。假设通过将PODA转化为部分碳化条件，所得涂层可以具有比没有碳化的PODA更高的电导率，并且同时仍然可以包含一些有机键，因此具有机械柔性以适应锂化期间Si的体积膨胀。结果表明，PODA在400 ℃下碳化可以获得这样的部分碳化状态。此外，部分转化的碳涂层可以为Si阳极的锂化和脱锂提供足够的导电性，同时大幅降低氧化还原反应的电荷转移电阻。此外，当硅阳极的体积膨胀不是很大时，部分转化碳包覆的空心硅纳米球具有良好的循环稳定性（类似于88%），即使该体积膨胀显著大于工程空隙空间（Si体积的47%）在部分转化的碳涂覆的中空Si纳米球内部可用，这明确地证实了部分转化的碳涂层在承受一定拉伸应变而不断裂方面的良好公差。本研究为今后的系统研究提供了一个新的方向，作为一种手段，以提供一种涂层上的硅材料具有足够的导电性沿着与能力，以承受一定的拉伸应变期间的体积膨胀的Si，从而提高循环稳定性的Si阳极。
In this study, we report the first investigation of the effectiveness of the partially converted carbon coating from polydopamine (PODA) to improve the cycle stability of Si anode for Li-ion batteries. It is hypothesized that by converting PODA to a partial carbonization condition, the resulting coating could have a higher electrical conductivity than PODA without carbonization, and at the same time may still contain some organic bonds and thus mechanical flexibility to accommodate the volume expansion of Si during lithiation. The results show that such a partial carbonization state can be obtained by carbonization of PODA at 400 degrees C. Furthermore, the partially converted carbon coating can offer sufficient electrical conductivity for lithiation and delithiation of Si anode while drastically reducing the charge transfer resistance for the redox reactions. In addition, the partially-converted-carbon coated hollow Si nano-spheres exhibit excellent cycle stability when the volume expansion of Si anode is not very large (similar to 88%) even though this volume expansion is significantly larger than the engineered void space (47% of the Si volume) available inside the partially-converted-carbon coated hollow Si nanospheres, unambiguously confirming the good tolerance of the partially converted carbon coating in withstanding some tensile strain without fracture. This study offers a new direction for systematic studies in the future as a means to provide a coating on Si material with sufficient electrical conductivity along with capability to withstand some tensile strain during the volume expansion of Si, thereby improving the cycle stability of Si anodes.