Shi Ying, Wang Zhenxing, Wen Lei, Pei Songfeng, Chen Ke, Li Hucheng, Cheng Hui-Ming, Li Feng
School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, 110016, China.
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China.
Adv Sci (Weinh). 2022 Apr;9(10):e2105419. doi: 10.1002/advs.202105419. Epub 2022 Feb 2.
Deteriorating interfacial contact under mechanical deformation induces large cracks and high charge transfer resistance, resulting in a severe capacity fading of flexible lithium-ion batteries (LIBs). Herein, an oxygen plasma treatment on a polymer separator combined with high-speed centrifugal spraying to construct ultrastable interfacial contacts is reported. With the treatment, abundant hydrophilic oxygen-containing functional groups are produced and ensure strong chemical adhesion between the separator and the active materials. With single walled carbon nanotubes (SWCNTs) sprayed onto the active materials, a dense thin film is formed as the current collector. Meanwhile, the centrifugal force caused by high-speed rotation together with van der Waals forces under fast evaporation produces a much closer interface between the current collector and the active materials. As a result of this ultrastable interfacial interaction, the integrated electrode shows no structural failure after 5000 bending cycles with the charge-transfer resistance as low as 35.8% and a Li-ion diffusion coefficient nearly 19 times of the untreated electrode. Flexible LIBs assembled with these integrated electrodes show excellent structural and electrochemical stability, and can work steadily under various deformed states and repeated bending. This work provides a new technique toward rational design of electrode configuration for flexible LIBs.
机械变形下不断恶化的界面接触会引发大裂纹和高电荷转移电阻，导致柔性锂离子电池（LIBs）严重的容量衰减。在此，报道了一种在聚合物隔膜上进行氧等离子体处理并结合高速离心喷涂以构建超稳定界面接触的方法。通过该处理，产生了大量亲水性含氧官能团，并确保了隔膜与活性材料之间的强化学粘附。将单壁碳纳米管（SWCNTs）喷涂到活性材料上，形成致密薄膜作为集流体。同时，高速旋转产生的离心力以及快速蒸发下的范德华力在集流体和活性材料之间产生了更紧密的界面。由于这种超稳定的界面相互作用，集成电极在5000次弯曲循环后没有结构失效，电荷转移电阻低至35.8%，锂离子扩散系数几乎是未处理电极的19倍。用这些集成电极组装的柔性LIBs表现出优异的结构和电化学稳定性，并且可以在各种变形状态和反复弯曲下稳定工作。这项工作为柔性LIBs电极结构的合理设计提供了一种新技术。
