Xing Yan, Chen Xiaopeng, Huang Yujia, Zhen Xiali, Wei Lujun, Zhong Xiqiang, Pan Wei
New Energy Technology Engineering Lab of Jiangsu Province, School of Science, Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210023, China.
State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
Materials (Basel). 2023 Jan 11;16(2):729. doi: 10.3390/ma16020729.
Ceramic electrolytes hold application prospects in all-solid-state lithium batteries (ASSLB). However, the ionic conductivity of ceramic electrolytes is limited by their large thickness and intrinsic resistance. To cope with this challenge, a two-dimensional (2D) vermiculite film has been successfully prepared by self-assembling expanded vermiculite nanosheets. The raw vermiculite mineral is first exfoliated to thin sheets of several atomic layers with about 1.2 nm interlayer channels by a thermal expansion and ionic exchanging treatment. Then, through vacuum filtration, the ion-exchanged expanded vermiculite (IEVMT) sheets can be assembled into thin films with a controllable thickness. Benefiting from the thin thickness and naturally lamellar framework, the as-prepared IEVMT thin film exhibits excellent ionic conductivity of 0.310 S·cm at 600 °C with low excitation energy. In addition, the IEVMT thin film demonstrates good mechanical and thermal stability with a low coefficient of friction of 0.51 and a low thermal conductivity of 3.9 × 10 W·m·K. This reveals that reducing the thickness and utilizing the framework is effective in increasing the ionic conductivity and provides a promising stable and low-cost candidate for high-performance solid electrolytes.
陶瓷电解质在全固态锂电池（ASSLB）中具有应用前景。然而，陶瓷电解质的离子电导率受到其较大厚度和固有电阻的限制。为应对这一挑战，通过自组装膨胀蛭石纳米片成功制备了二维（2D）蛭石薄膜。首先，通过热膨胀和离子交换处理将原始蛭石矿物剥离成具有约1.2 nm层间通道的几个原子层的薄片。然后，通过真空过滤，可将离子交换膨胀蛭石（IEVMT）片材组装成厚度可控的薄膜。得益于其薄的厚度和天然的层状结构，所制备的IEVMT薄膜在600°C时表现出0.310 S·cm的优异离子电导率，且激发能较低。此外，IEVMT薄膜具有良好的机械和热稳定性，摩擦系数低至0.51，热导率低至3.9×10 W·m·K。这表明减小厚度并利用其结构对于提高离子电导率是有效的，并为高性能固体电解质提供了一种有前景的稳定且低成本的候选材料。
