Empa , Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland.
ACS Appl Mater Interfaces. 2018 Dec 26;10(51):44494-44500. doi: 10.1021/acsami.8b16519. Epub 2018 Dec 11.
Using an epitaxial thin-film model system deposited by pulsed laser deposition (PLD), we study the Li-ion conductivity in LiTiO, a common anode material for Li-ion batteries. Epitaxy, phase purity, and film composition across the film thickness are verified employing out-of-plane and in-plane X-ray diffraction, transmission electron microscopy, time-of-flight mass spectrometry, and elastic recoil detection analysis. We find that epitaxial LiTiO behaves like an ideal ionic conductor that is well described by a parallel RC equivalent circuit, with an ionic conductivity of 2.5 × 10 S/cm at 230 °C and an activation energy of 0.79 eV in the measured temperature range of 205 to 350 °C. Differently, in a co-deposited polycrystalline LiTiO thin film with an average in-plane grain size of <10 nm, a more complex behavior with contributions from two distinct processes is observed. Ultimately, epitaxial LiTiO thin films can be grown by PLD and reveal suitable transport properties for further implementation as zero-strain and grain boundary free anodes in future solid-state microbattery designs.
我们使用脉冲激光沉积（PLD）沉积的外延薄膜模型系统来研究 LiTiO 的锂离子电导率，LiTiO 是锂离子电池常用的阳极材料。采用面外和面内 X 射线衍射、透射电子显微镜、飞行时间质谱和弹性反冲探测分析，验证了外延 LiTiO 的层状结构、相纯度和薄膜成分在整个薄膜厚度上的均匀性。我们发现外延 LiTiO 表现得像一个理想的离子导体，可以很好地用并联 RC 等效电路来描述，在 230°C 时的离子电导率为 2.5×10 S/cm，在 205 至 350°C 的测量温度范围内的激活能为 0.79 eV。相比之下，在具有 <10nm 平均面内晶粒尺寸的共沉积多晶 LiTiO 薄膜中，观察到具有两个不同过程贡献的更复杂行为。最终，通过 PLD 可以生长外延 LiTiO 薄膜，并表现出适合未来固态微电池设计中作为零应变和无晶界的阳极的传输性能。
