Abstract All solid-state Li-ion batteries offer unprecedented improvements in energy density and safety compared to contemporary Li-ion batteries. As one of the most common oxide cathode materials for traditional Li-ion batteries, LiCoO2 (LCO) is also under consideration for use in all solid-state batteries. However, differences in the coefficients of thermal expansion (CTE) between LCO and the solid electrolyte during composite electrode fabrication, and the differential expansion and contraction during electrochemical cycling resulting from Li insertion and de-insertion, will cause stresses resulting in battery capacity fade. To characterize the thermo-mechanical properties, this study utilized hot pressing to prepare high relative density (95%) LCO polycrystalline pellets. The elastic modulus (E), shear modulus (G), hardness (H), and Poisson’s ratio (υ) of LCO were determined to be ∼191 GPa, ∼80 GPa, ∼8.2 GPa (at peak indentation loads ≤5 mN), and 0.24, respectively. The CTE was determined to be ∼1.3 × 10−5/°C over the temperature range 50–400 °C. We believe these data are important to predict or increase the cycle life of commercially available LCO as a cathode material for state-of-the-art Li-ion and advanced solid-state batteries.

中文翻译：

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钴酸锂（LiCoO 2 ）的弹性

摘要 与当代锂离子电池相比，全固态锂离子电池在能量密度和安全性方面提供了前所未有的改进。作为传统锂离子电池最常见的氧化物正极材料之一，LiCoO2 (LCO) 也在考虑用于所有固态电池。然而，在复合电极制造过程中，LCO 和固体电解质之间的热膨胀系数 (CTE) 的差异，以及锂嵌入和脱嵌导致的电化学循环过程中的膨胀和收缩差异，将导致应力导致电池容量衰减。为了表征热机械性能，本研究利用热压制备高相对密度 (95%) LCO 多晶颗粒。弹性模量（E）、剪切模量（G）、硬度（H）、LCO 的泊松比 (υ) 分别为~191 GPa、~80 GPa、~8.2 GPa（峰值压痕载荷≤5 mN）和0.24。在 50–400 °C 的温度范围内，CTE 被确定为 ~1.3 × 10-5/°C。我们相信这些数据对于预测或增加市售 LCO 作为最先进的锂离子和先进固态电池的阴极材料的循环寿命很重要。