Seo Duck-Hyeon, Lee Jun-Seok, Yun Sang-Du, Yang Jeong-Hyeon, Huh Sun-Chul, Sung Yon-Mo, Jeong Hyo-Min, Noh Jung-Pil
Department of Energy & Mechanical Engineering and Institute of Marine Industry, Gyeongsang National University, 2 Tongyeonghaean-daero, Tongyeong 53064, Korea.
Department of Mechanical System Engineering, Gyeongsang National University, 2 Tongyeonghaean-daero, Tongyeong 53064, Korea.
Materials (Basel). 2022 Apr 5;15(7):2665. doi: 10.3390/ma15072665.
Sn is a promising candidate anode material with a high theoretical capacity (994 mAh/g). However, the drastic structural changes of Sn particles caused by their pulverization and aggregation during charge-discharge cycling reduce their capacity over time. To overcome this, a TiNi shape memory alloy (SMA) was introduced as a buffer matrix. Sn/TiNi SMA multilayer thin films were deposited on Cu foil using a DC magnetron sputtering system. When the TiNi alloy was employed at the bottom of a Sn thin film, it did not adequately buffer the volume changes and internal stress of Sn, and stress absorption was not evident. However, an electrode with an additional top layer of room-temperature-deposition TiNi (TiNi(RT)) lost capacity much more slowly than the Sn or Sn/TiNi electrodes, retaining 50% capacity up to 40 cycles. Moreover, the charge-transfer resistance decreased from 318.1 Ω after one cycle to 246.1 Ω after twenty. The improved cycle performance indicates that the TiNi(RT) and TiNi-alloy thin films overall held the Sn thin film. The structure was changed so that Li and Sn reacted well; the stress-absorption effect was observed in the TiNi SMA thin films.
锡是一种具有高理论容量（994毫安时/克）的有前景的负极材料候选物。然而，在充放电循环过程中，锡颗粒因粉化和聚集导致的剧烈结构变化会随着时间降低其容量。为克服这一问题，引入了一种钛镍形状记忆合金（SMA）作为缓冲基体。使用直流磁控溅射系统在铜箔上沉积锡/钛镍形状记忆合金多层薄膜。当钛镍合金置于锡薄膜底部时，它不能充分缓冲锡的体积变化和内应力，应力吸收不明显。然而，具有额外室温沉积钛镍（TiNi(RT)）顶层的电极容量衰减比锡或锡/钛镍电极慢得多，在40次循环内保持50%的容量。此外，电荷转移电阻从一个循环后的318.1Ω降至二十个循环后的246.1Ω。循环性能的改善表明TiNi(RT)和钛镍合金薄膜总体上支撑着锡薄膜。结构发生了变化，使得锂和锡能够良好反应；在钛镍形状记忆合金薄膜中观察到了应力吸收效应。
