Lee Kikang, Yoon Sungho, Hong Sunghoon, Kim Hyunmi, Oh Kyuhwan, Moon Jeongtak
Research and Development Center, MK Electron, Yongin-si 17030, Korea.
Department of Materials Science and Engineering, Seoul National University, Seoul-si 08826, Korea.
Materials (Basel). 2022 Jun 13;15(12):4189. doi: 10.3390/ma15124189.
Silicon-based anodes can increase the energy density of Li-ion batteries (LIBs) owing to their large weights and volumetric capacities. However, repeated charging and discharging can rapidly deteriorate the electrochemical properties because of a large volume change in the electrode. In this study, a commercial Fe-Si powder was coated with AlO layers of different thicknesses via atomic layer deposition (ALD) to prevent the volume expansion of Si and suppress the formation of crack-induced solid electrolyte interfaces. The AlO content was controlled by adjusting the trimethyl aluminum exposure time, and higher AlO contents significantly improved the electrochemical properties. In 300 cycles, the capacity retention rate of a pouch full-cell containing the fabricated anodes increased from 69.8% to 72.3% and 79.1% depending on the AlO content. The powder characterization and coin and pouch cell cycle evaluation results confirmed the formation of an AlO layer on the powder surface. Furthermore, the expansion rate observed during the charging/discharging of the pouch cell indicated that the deposited layer suppressed the powder expansion and improved the cell stability. Thus, the performance of an LIB containing Si-alloy anodes can be improved by coating an ALD-synthesized protective AlO layer.
硅基阳极由于其较大的重量和体积容量，可以提高锂离子电池（LIBs）的能量密度。然而，由于电极中较大的体积变化，反复充电和放电会迅速使电化学性能恶化。在本研究中，通过原子层沉积（ALD）在商业Fe-Si粉末上涂覆不同厚度的AlO层，以防止Si的体积膨胀并抑制裂纹诱导的固体电解质界面的形成。通过调整三甲基铝暴露时间来控制AlO含量，较高的AlO含量显著改善了电化学性能。在300次循环中，根据AlO含量的不同，包含制备阳极的软包全电池的容量保持率从69.8%提高到72.3%和79.1%。粉末表征以及硬币电池和软包电池的循环评估结果证实了在粉末表面形成了AlO层。此外，在软包电池充电/放电过程中观察到的膨胀率表明，沉积层抑制了粉末膨胀并提高了电池稳定性。因此，通过涂覆ALD合成的保护性AlO层，可以提高含Si合金阳极的LIB的性能。
