Kotobuki Masashi, Lei Houhua, Chen Yu, Song Shufeng, Xu Chaohe, Hu Ning, Molenda Janina, Lu Li
Department of Mechanical Engineering, National University of Singapore 9 Engineering Drive 1 Singapore 117576 Singapore
National University of Singapore Suzhou Research Institute Dushu Lake Science and Education Innovation District Suzhou 215123 P. R. China.
RSC Adv. 2019 Apr 15;9(21):11670-11675. doi: 10.1039/c9ra00711c. eCollection 2019 Apr 12.
The thickness of a solid electrolyte influences the performance of all-solid-state batteries due to increased impedance with a thick electrolyte. Thin solid electrolytes are favourable to improve the performance of all-solid-state batteries due to the short Li ion diffusion path and small volume of the solid electrolytes. Therefore, the preparation of thin solid electrolyte is one of the key process techniques for development of all-solid-state batteries. In this study, thin LiGeAl(PO) solid electrolyte with a Na super ion conductor structure is prepared by diamond wire slicing. The LiGeAl(PO) solid electrolyte is prepared by melt-quenching followed by crystallization at 800 °C for 8 h, after which the crystallized LiGeAl(PO) rod is subjected to wire slicing. Thin LiGeAl(PO) with a thickness of 200 μm is obtained. The crystal structure and cross-sectional morphology are not affected by the slicing. The total Li conductivity of the thin LiGeAl(PO) and activation energy are 3.3 × 10 S cm and 0.32 eV, respectively. The thickness and total conductivity are comparable to those of LiGeAl(PO) prepared by the tape-casting method which needs several steps to prepare LiGeAl(PO) tape-sheet and high temperature and a long sintering process. The ionic transference number of the thin LiGeAl(PO) is 0.999. The diamond wire slicing is a useful method to prepare thin solid electrolytes.
固态电解质的厚度会影响全固态电池的性能，因为较厚的电解质会增加阻抗。薄固态电解质有利于提高全固态电池的性能，这是由于锂离子扩散路径短且固态电解质体积小。因此，制备薄固态电解质是全固态电池发展的关键工艺技术之一。在本研究中，采用金刚石线切割法制备了具有钠超离子导体结构的薄LiGeAl(PO)固态电解质。LiGeAl(PO)固态电解质通过熔融淬火制备，然后在800℃下结晶8小时，之后将结晶的LiGeAl(PO)棒进行线切割。得到了厚度为200μm的薄LiGeAl(PO)。晶体结构和横截面形态不受切割的影响。薄LiGeAl(PO)的总Li电导率和活化能分别为3.3×10 S cm和0.32 eV。其厚度和总电导率与通过流延法制备的LiGeAl(PO)相当，流延法需要几个步骤来制备LiGeAl(PO)带材片，且需要高温和长时间的烧结过程。薄LiGeAl(PO)的离子迁移数为0.999。金刚石线切割是制备薄固态电解质的一种有用方法。
