Electrochemical Behavior of Drawn Thin-Film Vitreous Lithium Metaphosphate
Electrochemical Behavior of Drawn Thin-Film Vitreous Lithium Metaphosphate
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DOI：
10.1021/acsaem.1c01809
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发表时间：
2021-10
影响因子：
6.4
通讯作者：
Jacob Wheaton;Steven J. Kmiec;Devon Schuler;C. Sorensen;Steve W. Martin
中科院分区：
文献类型：
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作者：
Jacob Wheaton;Steven J. Kmiec;Devon Schuler;C. Sorensen;Steve W. Martin
通过软化和拉制铸造和退火的 LiPO3 玻璃预制件，首次拉制出厚度为 35 至 800 μm 的偏磷酸锂 (LiPO3) 薄膜玻璃态固态电解质 (GSSE) 带。使用拉曼光谱证实薄膜玻璃的短程有序结构和组成与块状玻璃 LiPO3 相同。使用电化学阻抗谱 (EIS) 研究了薄膜 GSSE 样品的锂离子电导率，结果与块体 LiPO3 玻璃的锂离子电导率基本相同。生成了作为薄膜厚度和温度函数的面积比电阻 (ASR) 模型，并将其与通过 EIS 生成的奈奎斯特图的等效电路拟合确定的电阻进行比较。生成的模型与实验确定的值进行了很好的比较。在 50 μm 厚的样品上进行对称电池循环，以确定电解质在施加电压和持续电流下的循环行为和耐久性。在对称电池循环中观察到 LiPO3 薄膜 GSSE 对锂金属的电化学稳定性的证据，因为在一定电流密度范围内发现了几乎完全平坦的欧姆行为循环平台。短路之前，在 90 °C 下获得了 65 μA/cm2 的临界电流密度，直流 (dc) Li 离子电导率为 10–6.5[Ω·cm]−1。虽然这些电流密度较低，但这是第一份将薄膜 GSSE 拉伸至高性能全固态锂电池所需厚度的报告，并且这种氧化物 GSSE 经验证的稳定性和耐用性有力地证明了拉伸薄膜 GSSE 材料，特别是那些具有较高电导率的材料，例如经过充分研究的硫化物玻璃，是制造薄的、易于加工的固态电解质的可行材料。 （SSE）并值得进一步研究。
Lithium metaphosphate (LiPO3) thin-film glassy solid-state electrolyte (GSSE) ribbons with thicknesses varying from 35 to 800 μm have been drawn for the first time through softening and drawing of a cast and annealed preform of LiPO3glass. The short-range order structure and composition of the thin-film glasses were confirmed to be identical to the bulk glass LiPO3using Raman spectroscopy. Electrochemical impedance spectroscopy (EIS) was used to investigate the Li ionic conductivity of the thin-film GSSE samples and was essentially the same as that of the bulk LiPO3glass. A model of area specific resistance (ASR) as a function of film thickness and temperature was generated and compared to resistances determined through equivalent circuit fitting of EIS generated Nyquist plots. The generated model compared well to the experimentally determined values. Symmetric cell cycling was conducted on the 50 μm thick samples to determine the cycling behavior and the durability of the electrolyte under applied voltage and sustained current. Evidence of the electrochemical stability of the LiPO3thin-film GSSE against lithium metal was observed in the symmetric cell cycling as nearly perfectly flat and ohmic behavior cycling plateaus were found over a range of current densities. Prior to shorting, a critical current density of 65 μA/cm2was obtained at 90 °C with a direct current (dc) Li ionic conductivity of 10–6.5[Ω·cm]−1. While these current densities are low, this is the first report of a thin-film GSSE drawn into thicknesses of that required for high performance all-solid-state lithium batteries, and the proven stability and durability of this oxide GSSE is strong evidence that drawn thin-film GSSE materials, especially those with higher conductivities such as the well-studied sulfide glasses, are viable materials from which to create thin, easily processable solid-state electrolytes (SSEs) and warrant further research.